getimagesize

(PHP 4, PHP 5, PHP 7, PHP 8)

getimagesize — 取得图像大小

说明

getimagesize(string $filename, array &$image_info = null): array|false

getimagesize() 函数将确定任何支持的指定图像文件的大小，并返回尺寸以及文件类型和 height/width 文本字符串，以在标准 HTML IMG 标签和对应的 HTTP 内容类型中使用。

getimagesize() 还可以在 image_info 参数中返回更多信息。

警告

此函数要求 filename 是有效的图像文件。如果提供的是非图像，可能会错误的识别为图像且函数会成功返回，但数组可能包含无意义的值。

不要使用 getimagesize() 识别指定的文件是否是有效的图像。请使用专业解决方案，比如 Fileinfo 扩展。

注意: 注意 JPC 和 JP2 是具有不同位深度的组件。此外，JP2 文件可能包含有多个 JPEG 2000 代码流，此情况下，getimagesize() 返回此文件顶层中碰到的第一个代码流的值。

注意: 从具有最高比特率的 icon 中检索有关 icon 的信息。

注意: GIF 图像由一个或多个帧组成，其中每个帧可能只占据图像的一部分。getimagesize() 报告的图像大小是整体大小（从逻辑屏幕描述符中读取）。

参数

filename: 此参数指定希望检索其信息的文件。可以指向本地文件或（配置允许）使用某个支持的流的远程文件。
image_info: 可选参数允许从图像文件中提取一些扩展信息。目前会将不同的 JPG APP 标记作为关联数组返回。一些程序使用这些 APP 标记在图像中嵌入文本信息。 A very common one is to embed » IPTC information in the APP13 marker. You can use the iptcparse() function to parse the binary APP13 marker into something readable.

注意:
image_info 仅支持 JFIF 文件。

返回值

返回信息最多包含 7 个元素。并非所有图像类型都包含 channels 和 bits 元素。

索引 0 和 1 分别包含图像的宽度和高度。

注意:
一些格式可能没有图像或者包含多个图像。在这种情况下，getimagesize() 可能无法正确确定图像大小。getimagesize() 此时会返回的宽高为 0。

索引 2 是表示图像类型的某个 IMAGETYPE_* 常量。

Index 3 is a text string with the correct height="yyy" width="xxx" string that can be used directly in an IMG tag.

mime 是图像对应的 MIME 类型。此信息可用于传递具有正确 HTTP Content-type 报头的图像：

示例 #1 getimagesize() 和 MIME 类型

<?php
$size = getimagesize($filename);
$fp = fopen($filename, "rb");
if ($size && $fp) {
    header("Content-type: {$size['mime']}");
    fpassthru($fp);
    exit;
} else {
    // error
}
?>

channels 对 RGB 图片为 3，对 CMYK 图像为 4。

bits 是每种颜色的位数。

对应一些图像类型，channels 和 bits 值的存在可能会让人困惑。 As an example, GIF always uses 3 channels per pixel, but the number of bits per pixel cannot be calculated for an animated GIF with a global color table.

失败时返回 false。

错误／异常

如果无法访问 filename 图像，getimagesize() 将生成 E_WARNING 级别的错误。读取错误时，getimagesize() 将生成 E_NOTICE 级别的错误。

更新日志

版本	说明
8.2.0	现在将正确返回 AVIF 图像的实际尺寸、bits 和 channels；以前，尺寸报告为 `0x0`，并且不会报告 bits 和 channels。
7.1.0	新增 WebP 支持。

示例

示例 #2 getimagesize() 示例

<?php
list($width, $height, $type, $attr) = getimagesize("img/flag.jpg");
echo "<img src=\"img/flag.jpg\" $attr alt=\"getimagesize() example\" />";
?>

示例 #3 getimagesize (URL)

<?php
$size = getimagesize("http://www.example.com/gifs/logo.gif");

// if the file name has space in it, encode it properly
$size = getimagesize("http://www.example.com/gifs/lo%20go.gif");

?>

示例 #4 getimagesize() 返回 IPTC

<?php
$size = getimagesize("testimg.jpg", $info);
if (isset($info["APP13"])) {
    $iptc = iptcparse($info["APP13"]);
    var_dump($iptc);
}
?>

注释

注意:
此函数不需要 GD 图象库。

参见

image_type_to_mime_type() - 取得 getimagesize、exif_read_data、exif_thumbnail、exif_imagetype 所返回的图像类型的 MIME 类型
exif_imagetype() - 判断一个图像的类型
exif_read_data() - 从一个图片文件中读取 EXIF 头信息
exif_thumbnail() - 检索图像的嵌入式缩略图
imagesx() - 取得图像宽度
imagesy() - 取得图像高度

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用户贡献的备注 24 notes

down

james dot relyea at zifiniti dot com ¶

15 years ago

As noted below, getimagesize will download the entire image before it checks for the requested information. This is extremely slow on large images that are accessed remotely. Since the width/height is in the first few bytes of the file, there is no need to download the entire file. I wrote a function to get the size of a JPEG by streaming bytes until the proper data is found to report the width and height:

<?php
// Retrieve JPEG width and height without downloading/reading entire image.
function getjpegsize($img_loc) {
    $handle = fopen($img_loc, "rb") or die("Invalid file stream.");
    $new_block = NULL;
    if(!feof($handle)) {
        $new_block = fread($handle, 32);
        $i = 0;
        if($new_block[$i]=="\xFF" && $new_block[$i+1]=="\xD8" && $new_block[$i+2]=="\xFF" && $new_block[$i+3]=="\xE0") {
            $i += 4;
            if($new_block[$i+2]=="\x4A" && $new_block[$i+3]=="\x46" && $new_block[$i+4]=="\x49" && $new_block[$i+5]=="\x46" && $new_block[$i+6]=="\x00") {
                // Read block size and skip ahead to begin cycling through blocks in search of SOF marker
                $block_size = unpack("H*", $new_block[$i] . $new_block[$i+1]);
                $block_size = hexdec($block_size[1]);
                while(!feof($handle)) {
                    $i += $block_size;
                    $new_block .= fread($handle, $block_size);
                    if($new_block[$i]=="\xFF") {
                        // New block detected, check for SOF marker
                        $sof_marker = array("\xC0", "\xC1", "\xC2", "\xC3", "\xC5", "\xC6", "\xC7", "\xC8", "\xC9", "\xCA", "\xCB", "\xCD", "\xCE", "\xCF");
                        if(in_array($new_block[$i+1], $sof_marker)) {
                            // SOF marker detected. Width and height information is contained in bytes 4-7 after this byte.
                            $size_data = $new_block[$i+2] . $new_block[$i+3] . $new_block[$i+4] . $new_block[$i+5] . $new_block[$i+6] . $new_block[$i+7] . $new_block[$i+8];
                            $unpacked = unpack("H*", $size_data);
                            $unpacked = $unpacked[1];
                            $height = hexdec($unpacked[6] . $unpacked[7] . $unpacked[8] . $unpacked[9]);
                            $width = hexdec($unpacked[10] . $unpacked[11] . $unpacked[12] . $unpacked[13]);
                            return array($width, $height);
                        } else {
                            // Skip block marker and read block size
                            $i += 2;
                            $block_size = unpack("H*", $new_block[$i] . $new_block[$i+1]);
                            $block_size = hexdec($block_size[1]);
                        }
                    } else {
                        return FALSE;
                    }
                }
            }
        }
    }
    return FALSE;
}
?>

down

nikolam3244 at gmail dot com ¶

6 years ago

There's a code snippet for getting JPEG image dimensions by getting only first few bytes of the file, but it doesn't work for PNG files, so I wrote one. It will download only the first 24 bytes instead of the whole image, and thus being much faster than getimagesize() and it will save bandwidth at the same time:

<?php
// Retrieve PNG width and height without downloading/reading entire image.
function getpngsize( $img_loc ) {
    $handle = fopen( $img_loc, "rb" ) or die( "Invalid file stream." );

    if ( ! feof( $handle ) ) {
        $new_block = fread( $handle, 24 );
        if ( $new_block[0] == "\x89" &&
            $new_block[1] == "\x50" &&
            $new_block[2] == "\x4E" &&
            $new_block[3] == "\x47" &&
            $new_block[4] == "\x0D" &&
            $new_block[5] == "\x0A" &&
            $new_block[6] == "\x1A" &&
            $new_block[7] == "\x0A" ) {
                if ( $new_block[12] . $new_block[13] . $new_block[14] . $new_block[15] === "\x49\x48\x44\x52" ) {
                    $width  = unpack( 'H*', $new_block[16] . $new_block[17] . $new_block[18] . $new_block[19] );
                    $width  = hexdec( $width[1] );
                    $height = unpack( 'H*', $new_block[20] . $new_block[21] . $new_block[22] . $new_block[23] );
                    $height  = hexdec( $height[1] );

                    return array( $width, $height );
                }
            }
        }

    return false;
}
?>

down

tomasz at trejderowski dot pl ¶

11 years ago

If you want to "convert" value returned by "getimagesize()" as index "2" into something more human-readable, you may consider using a function like this one:

    $imageTypeArray = array
    (
        0=>'UNKNOWN',
        1=>'GIF',
        2=>'JPEG',
        3=>'PNG',
        4=>'SWF',
        5=>'PSD',
        6=>'BMP',
        7=>'TIFF_II',
        8=>'TIFF_MM',
        9=>'JPC',
        10=>'JP2',
        11=>'JPX',
        12=>'JB2',
        13=>'SWC',
        14=>'IFF',
        15=>'WBMP',
        16=>'XBM',
        17=>'ICO',
        18=>'COUNT'  
    );
    
    $size = getimagesize($filename);
    
    $size[2] = $imageTypeArray[$size[2]];

Or something similar.

down

php dot net at dannysauer dot com ¶

19 years ago

Note that, if you're going to be a good programmer and use named constatnts (IMAGETYPE_JPEG) rather than their values (2), you want to use the IMAGETYPE variants - IMAGETYPE_JPEG, IMAGETYPE GIF, IMAGETYPE_PNG, etc.  For some reason, somebody made a horrible decision, and IMG_PNG is actually 4 in my version of PHP, while IMAGETYPE_PNG is 3.  It took me a while to figure out why comparing the type against IMG_PNG was failing...

down

simon dot waters at surevine dot com ¶

9 years ago

Note: getimage size doesn't attempt to validate image file formats

It is possible for malformed GIF images to contain PHP and still have valid dimensions.

Programmers need to ensure such images are validated by other tools, or never treated as PHP or other executable types (enforcing appropriate extensions, avoiding user controlled renaming, restricting uploaded images to areas of the website where PHP is not enabled).

http://ha.ckers.org/blog/20070604/passing-malicious-php-through-getimagesize/

down

redcore at gmail dot com ¶

17 years ago

It's always good to check out an image's dimensions while attempting to upload to your server or database...especially if it's going to be displayed on a page that doesn't accomodate images beyond a particular size.

<?php

$tmpName = $_FILES['userfile']['tmp_name'];
        
list($width, $height, $type, $attr) = getimagesize($tmpName);

if($width>275 || $height>275)
{
die("exceeded image dimension limits.");
}

?>

down

utilmind ¶

13 years ago

Here is the function which determines whether the PNG image contains alpha or not:



<?php

function is_alpha_png($fn){

  return (ord(@file_get_contents($fn, NULL, NULL, 25, 1)) == 6);

}

?>



The color type of PNG image is stored at byte offset 25. Possible values of that 25'th byte is:

 * 0 - greyscale

 * 2 - RGB

 * 3 - RGB with palette

 * 4 - greyscale + alpha

 * 6 - RGB + alpha

down

info at alex-lawrence dot com ¶

16 years ago

Could be useful (didn´t know where to post it):

function getImageErrors( $filename, $type = "", $minWidth = 0, $minHeight = 0, $maxWidth = 0, $maxHeight = 0, $maxFileSize = 0 )
{
    $errors = array();
    if ( file_exists( $filename ) )
    {
        $ending = substr( $filename, strpos( $filename, "." ) );
        if ( is_array( $type ) )
        {
            $isTypeOf = false;
            foreach( $type as $eachtype )
            {
                if ( $ending == $eachtype )
                {
                    $isTypeOf = true;
                }
            }
            if ( ! $isTypeOf )
            {
                $errors[ 'type' ] = $ending;
            }
        }
        elseif ( $type != "" )
        {
            if ( $ending != $type )
            {
                $errors[ 'type' ] = $ending;
            }
        }
        $size = getimagesize( $filename );
        if ( $size[ 0 ] < $minWidth )
        {
            $errors[ 'minWidth' ] = $size[ 0 ];
        }
        if ( $size[ 1 ] < $minHeight )
        {
            $errors[ 'minHeight' ] = $size[ 1 ];
        }
        if ( ( $maxWidth > $minWidth ) && ( $size[ 0 ] > $maxWidth ) )
        {
            $errors[ 'maxWidth' ] = $size[ 0 ];
        }
        if ( ( $maxHeight > $minHeight ) && ( $size[ 1 ] > $maxHeight ) )
        {
            $errors[ 'maxHeight' ] = $size[ 1 ];
        }
        if ( ( $maxFileSize > 0 ) && ( filesize( $filename ) > $maxFileSize ) )
        {
            $errors[ 'maxFileSize' ] = filesize( $filename );
        }
    }
    else
    {
        $errors[ 'filename' ] = "not existing";
    }
    return ( count( $errors ) > 0 ? $errors : null );
}

down

Steve ¶

13 years ago

The list of defined IMAGETYPE_ constants is on the manual page for exif_imagetype:

http://www.php.net/manual/en/function.exif-imagetype.php

down

shmohel at gmail dot com ¶

16 years ago

Rather than making a lengthy function that essentially runs twice (once as width, once as height) I came up with a helpful function that uses variable variables to set a maximum height/width. Hope someone finds this helpful.

function scaleimage($location, $maxw=NULL, $maxh=NULL){
    $img = @getimagesize($location);
    if($img){
        $w = $img[0];
        $h = $img[1];

        $dim = array('w','h');
        foreach($dim AS $val){
            $max = "max{$val}";
            if(${$val} > ${$max} && ${$max}){
                $alt = ($val == 'w') ? 'h' : 'w';
                $ratio = ${$alt} / ${$val};
                ${$val} = ${$max};
                ${$alt} = ${$val} * $ratio;
            }
        }

        return("<img src='{$location}' alt='image' width='{$w}' height='{$h}' />");
    }
}

down

info at personalmis dot com ¶

16 years ago

Seems the various ways people are trying to proportionaly scale an image, up or down, could be more straight forward if one remembers ones algebra.

The formula is, y = mx, where m is the slope of the line. This is the ratio of y:x or m = y/x.

So if...

// max values for x and y
$y_max = 600;
$x_max = 800;

// image size
$y1 = 2000;
$x1 = 3000;

// use width for scaling
if ($x1 > $x_max)
{
    // find slope 
    $m = $y1/$x1;
    // set x side to max
    $x2 = $x_max;
    // set y side to a proportional size
    $y2 = $m * $x1;
}

The new image proportionally scaled will be x2 = 800, y2 = 533 (rounded).

To do it from the y side, simply reverse the x's and y's.

down

geoff at spacevs dot com ¶

15 years ago

This function returns the width and height of a JPEG image from a string, allowing the dimensions of images stored in a database to be retrieved without writing them to the disk first, or using "imagecreatefromstring" which is very slow in comparison.

<?PHP
function getJPEGImageXY($data) {
        $soi = unpack('nmagic/nmarker', $data);
        if ($soi['magic'] != 0xFFD8) return false;
        $marker = $soi['marker'];
        $data   = substr($data, 4);
        $done   = false;

        while(1) {
                if (strlen($data) === 0) return false;
                switch($marker) {
                        case 0xFFC0:
                                $info = unpack('nlength/Cprecision/nY/nX', $data);
                                return array($info['X'], $info['Y']);
                                break;

                        default:
                                $info   = unpack('nlength', $data);
                                $data   = substr($data, $info['length']);
                                $info   = unpack('nmarker', $data);
                                $marker = $info['marker'];
                                $data   = substr($data, 2);
                                break;
                }
        }
}
?>

Doing this 10,000 times takes 0.43 seconds, compared with using imagecreatefromstring/imagesx/imagesy which takes around 1.52 seconds to do the same.

Do not use this instead of getimagesize when dealing with files, getimagesize is much faster coming in at 0.15 seconds.

down

cloned at clonedmadman dot com ¶

16 years ago

Well, I am making a script which will resize the image when uploaded, however, i am making a multi-uploader, so i came across with a problem: an efficient way of getting a pictures height and width and storing them in an array to resize later. This is what i came up with:

<?php
$links = array("test1.jpg", "test2.png");
$sizearray = array();
$count = count($links);
for($i = 0; $i < $count; $i++) {
    $size = getimagesize($links[$i]);
    list($width, $height) = $size;
    $sizearray[$links[$i]] = array("width" => $width, "height" => $height);
}
print_r($sizearray);
// which will print out: Array ( [test1.jpg] => Array ( [width] => 300 [height] => 400 ) [test2.png] => Array ( [width] => 680 [height] => 100 ) )
?>

down

diablx at hotmail dot com ¶

20 years ago

I'm sorry for they other scripts, but I made one mistake about the image resizing... here is a working script !
<?
    // Some configuration variables !
    $maxWidth = 90;
    $maxHeight = 90;
    $maxCols = 8;
    $webDir = "https://localhost/images/";
    $localDir = $_SERVER['DOCUMENT_ROOT']."/images/";

    $AutorisedImageType = array ("jpg", "jpeg", "gif", "png");
?>

<center>
<table border='1' cellspacing='5' cellpadding='5' style="border-collapse:collapse; border-style: dotted">
<tr>
   <?
   // Open localDir
   $dh = opendir($localDir);
   while (false !== ($filename = readdir($dh))) {
       $filesArray[] = $filename;
   }

   // Display and resize
   foreach ($filesArray as $images) {
   
       $ext = substr($images, strpos($images, ".")+1, strlen($images));
       
       if( in_array($ext, $AutorisedImageType) ) {

           list($width, $height, $type, $attr) = @getimagesize( $localDir.$images );

            $xRatio = $maxWidth / $width; 
            $yRatio = $maxHeight / $height; 
            
            if ( ($width <= $maxWidth) && ($height <= $maxHeight) ) { 
              $newWidth = $width; 
              $newHeight = $height; 
            } 
            else if (($xRatio * $height) < $maxHeight) { 
              $newHeight = ceil($xRatio * $height); 
              $newWidth = $maxWidth; 
            } 
            else { 
              $newWidth = ceil($yRatio * $width); 
              $newHeight = $maxHeight; 
            } 
           
           if($i == $maxCols) {
               echo "</tr><tr>";
               $i = 0;
           }
           echo "<td align='center' valign='middle' width='$maxWidth' height='$maxHeight'><img src='".$webDir.$images."' width='$newWidth' height='$newHeight'></td>";
           $i++;
       }
   }
?>
</tr>
</table>
</center>

down

kazuya ¶

10 years ago

i made function img_resize($path,$tmp_name,$new_name,$new_width)
this could be useful.

<?php

$new_file = img_resize("./img/", "test.jpg","copy_test.jpg",300);
echo "<IMG src = '$new_file'>";

function img_resize($path,$tmp_name,$new_name,$new_width){
    if (!file_exists($path.$filename)){
        echo "file not found!";
        exit;
    }
    if (!is_writable($path)){
        echo "error:permission denied!";
        exit;
    }
    list($width, $height) = getimagesize($path . $tmp_name);
    $new_height = abs($new_width * $height / $width); 
    $image_p = imagecreatetruecolor($new_width, $new_height);
    $image = imagecreatefromjpeg($path . $tmp_name); 
    imagecopyresampled($image_p, $image, 0, 0, 0, 0,
                        $new_width, $new_height, $width, $height); 
    imagejpeg($image_p, $path . $new_name); 
    return $path.$new_name;
}

?>

down

alexyam at live dot com ¶

12 years ago

I wanted to use getimagesize() on .SWF files stored in the database as blob data and couldn't find a simple solution, so I created my own.

I am releasing this code under the MIT license to save everyone some time:

<?php
/*
    ----------------------------------------------------------------------
    PHP Blob Data As File Stream v1.0 (C) 2012 Alex Yam <alexyam@live.com>
    This code is released under the MIT License.
    ----------------------------------------------------------------------
    [Summary]

    A simple class for PHP functions to read and write blob data as a file
    using a stream wrapper.

    Particularly useful for running getimagesize() to get the width and
    height of .SWF Flash files that are stored in the database as blob data.

    Tested on PHP 5.3.10.

    ----------------------------------------------------------------------    
    [Usage Example]

    //Include
        include('./blob_data_as_file_stream.php');

    //Register the stream wrapper
        stream_wrapper_register("BlobDataAsFileStream", "blob_data_as_file_stream");

    //Fetch a .SWF file from the Adobe website and store it into a variable.
    //Replace this with your own fetch-swf-blob-data-from-database code.
        $swf_url = 'http://www.adobe.com/swf/software/flash/about/flashAbout_info_small.swf';
        $swf_blob_data = file_get_contents($swf_url);
    
    //Store $swf_blob_data to the data stream
        blob_data_as_file_stream::$blob_data_stream = $swf_blob_data;
    
    //Run getimagesize() on the data stream
        $swf_info = getimagesize('BlobDataAsFileStream://');
        var_dump($swf_info);

    ----------------------------------------------------------------------
    [Usage Output]

    array(5) {
      [0]=>
      int(159)
      [1]=>
      int(91)
      [2]=>
      int(13)
      [3]=>
      string(23) "width="159" height="91""
      ["mime"]=>
      string(29) "application/x-shockwave-flash"
    }

*/

class blob_data_as_file_stream {

    private static $blob_data_position = 0;
    public static $blob_data_stream = '';

    public static function stream_open($path,$mode,$options,&$opened_path){
        static::$blob_data_position = 0;
        return true;
    }

    public static function stream_seek($seek_offset,$seek_whence){
        $blob_data_length = strlen(static::$blob_data_stream);
        switch ($seek_whence) {
            case SEEK_SET:
                $new_blob_data_position = $seek_offset;
                break;
            case SEEK_CUR:
                $new_blob_data_position = static::$blob_data_position+$seek_offset;
                break;
            case SEEK_END:
                $new_blob_data_position = $blob_data_length+$seek_offset;
                break;
            default:
                return false;
        }
        if (($new_blob_data_position >= 0) AND ($new_blob_data_position <= $blob_data_length)){
            static::$blob_data_position = $new_blob_data_position;
            return true;
        }else{
            return false;
        }
    }

    public static function stream_tell(){
        return static::$blob_data_position;
    }

    public static function stream_read($read_buffer_size){
        $read_data = substr(static::$blob_data_stream,static::$blob_data_position,$read_buffer_size);
        static::$blob_data_position += strlen($read_data);
        return $read_data;
    }

    public static function stream_write($write_data){
        $write_data_length=strlen($write_data);
        static::$blob_data_stream = substr(static::$blob_data_stream,0,static::$blob_data_position).
            $write_data.substr(static::$blob_data_stream,static::$blob_data_position+=$write_data_length);
        return $write_data_length;
    }

    public static function stream_eof(){
        return static::$blob_data_position >= strlen(static::$blob_data_stream);
    }

}
?>

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ajreading at classixshop dot com ¶

19 years ago

A simple piece of code i wrote to proportionally resize an image to a max height and width then display it

<?php
// Max height and width
$max_width = 100;
$max_height = 100;

// Path to your jpeg

$upfile '/path/to/file.jpg';
    Header("Content-type: image/jpeg");
    
    $size = GetImageSize($upfile); // Read the size
          $width = $size[0];
          $height = $size[1];
          
          // Proportionally resize the image to the
          // max sizes specified above
          
          $x_ratio = $max_width / $width;
          $y_ratio = $max_height / $height;

          if( ($width <= $max_width) && ($height <= $max_height) )
          {
               $tn_width = $width;
               $tn_height = $height;
          }
          elseif (($x_ratio * $height) < $max_height)
          {
               $tn_height = ceil($x_ratio * $height);
               $tn_width = $max_width;
          }
          else
          {
               $tn_width = ceil($y_ratio * $width);
               $tn_height = $max_height;
          }
     // Increase memory limit to support larger files
     
     ini_set('memory_limit', '32M');
     
     // Create the new image!
     $src = ImageCreateFromJpeg($upfile);
     $dst = ImageCreateTrueColor($tn_width, $tn_height);
     ImageCopyResized($dst, $src, 0, 0, 0, 0, $tn_width, $tn_height, $width, $height);
     ImageJpeg($dst);
// Destroy the images
ImageDestroy($src);
ImageDestroy($dst);
?>

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freecorvette at gmail dot com ¶

7 years ago

For some images, using getimagesize() without the second parameter will return the correct info, but when you add the second parameter it will return false. This is most likely a bug (and it has been reported as such), but meanwhile, if you encounter this problem, a workaround is to use exif_read_data().

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Jesus Zamora ¶

13 years ago

Returns a array with 4 elements.
The 0 index is the width of the image in pixels.
The 1 index is the height of the image in pixels.
The 2 index is a flag for the image type:

1 = GIF, 2 = JPG, 3 = PNG, 4 = SWF, 5 = PSD, 6 = BMP, 7 = TIFF(orden de bytes intel), 8 = TIFF(orden de bytes motorola), 9 = JPC, 10 = JP2, 11 = JPX, 12 = JB2, 13 = SWC, 14 = IFF, 15 = WBMP, 16 = XBM. 

The 3 index contains ' height="yyy" width="xxx" '

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anonymous ¶

15 years ago

Note that if you specify a remote file (via a URL) to check the size of, PHP will first download the remote file to your server.

If you're using this function to check the size of user provided image links, this could constitute a security risk.  A malicious user could potentially link to a very large image file and cause PHP to download it.  I do not know what, if any, file size limits are in place for the download.  But suppose the user provided a link to an image that was several gigabytes in size?

It would be nice if there were a way to limit the size of the download performed by this function.  Hopefully there is already a default with some sensible limits.

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mail at soylentgreens dot com ¶

19 years ago

How about this for cropping images...

<?php

$imgfile = "img.jpg";
$cropStartX = 300;
$cropStartY = 250;
$cropW   = 200;
$cropH   = 200;

// Create two images
$origimg = imagecreatefromjpeg($imgfile);
$cropimg = imagecreatetruecolor($cropW,$cropH);

// Get the original size
list($width, $height) = getimagesize($imgfile);

// Crop
imagecopyresized($cropimg, $origimg, 0, 0, $cropStartX, $cropStartY, $width, $height, $width, $height);

// TODO: write code to save new image
// or, just display it like this:
header("Content-type: image/jpeg");
imagejpeg($cropimg);

// destroy the images
imagedestroy($cropimg);
imagedestroy($origimg);

?>

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-1

user at example dot net ¶

16 years ago

When validating images, allways check both, image type *AND* file extension!

Because most image types allow sections for comments or other irrelevant data. Those section can be used to infiltrate php code onto the server. If these files are stored as sent by the client, files with a ".php" extension can be executed and do tremendous harm.

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-1

pfarthing at hotmail dot com ¶

16 years ago

Correction: to find $y2 it should be...

// set y side to a proportional size
$y2 = $m * $x_max; // not $x1

Thanks Norbert =)

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-2

Coodiss at w3bbix dot net ¶

19 years ago

Heres a easy way to scale images to the <td> that they are in
*this is broken up so anyone can understand it :)

<?
$imageinfo = getimagesize("images/picture.jpg");
          
$ix=$imageinfo[0];
$iy=$imageinfo[1];

$widthscale = $ix/175;  //<TD> WIDTH
$heightscale = $iy/175; //<TD> HEIGHT

if($widthscale < 1)
$nwidth = $ix*$widthscale;
else
$nwidth = $ix/$widthscale;

if($heightscale < 1)
$nheight = $iy*$heightscale;
else
$nheight = $iy/$heightscale;

?>