Resize images with PHP script

Did you ever try to resize many images at once? I did, and I wrote PHP script for that purpose. Anyway, after I selected few images from my photo album, I realized that every image was about 500KB and resolution of 1600x1200. This seems too big. Images should be smaller and lighter for upload. Is GIMP capable to resize all images inside directory - I don't know, but opening, resizing and saving every image, will certainly take some time.

This small command line PHP script will help you to resize all JPG images inside current directory. Yes, you will find a lot of solutions with BASH scripts, but I decided to write my own command line PHP script. I didn't want to use GD PHP functions for image processing. Instead of GD library, I used utilities from ImageMagick suite of tools: identify and convert. This way, PHP script is shorter and easier to understand.

• identify - describes the format and characteristics of one or more image files
• convert - convert between image formats as well as resize an image, blur, crop, despeckle, dither, draw on, flip, join, re-sample, and much more

Script was developed on Linux - Fedora Core 9 and tested on Fedora Core 9 and Fedora Core 10.

#!/usr/bin/php
<?
/*
 * usage:
 * resize.php [destination_width] [destination_height]
 *
 * destination_width and destination_height are optional
 * parameters for destination resize geometry
 *
 * resize.php will create output directory to save resized
 * images leaving originals intact
 *
 * This script uses "identify" and "convert" utilities which
 * are members of the ImageMagick suite of tools
 *
 */

// input arguments for destination image size
$w2 = $argv[1]; // image width
$h2 = $argv[2]; // image height

// both values should be numeric or use default size 800x600
if (!is_numeric($w2) || !is_numeric($h2)){
	$w2 = 800; // default image width
	$h2 = 600; // default image height
}

// prepare directory name for saving resized images
// directory name will look like "_800x600"
$dir = "_$w2" . "x$h2";

// create directory (inside current directory) for saving
// resized images (@ means to be quiet - don't display
// warning if directory alredy exists)
@mkdir($dir);

// read files inside current directory
$files = scandir('.');

// open loop for all fetched files in current directory
foreach ($files as $file){
	// convert file name to lower case
	$file_lowercase = strtolower($file);
	// if file extension is jpg then process image
	if (substr($file_lowercase, -3) == 'jpg'){
		// describe image format and image characteristics
		$identify = shell_exec("identify $file");
		// read image geometry
		preg_match('/(\d+)x(\d+)/', $identify, $matches);
		$g1 = $matches[0]; // image geometry
		$w1 = $matches[1]; // image width
		$h1 = $matches[2]; // image height
		// prepare destination image geometry
		if ($w1 < $h1) $g2 = $h2 .'x' .$w2;
		else           $g2 = $w2 .'x' .$h2;
		// print current image status
		print "$file ($g1) -> $dir/$file_lowercase ($g2)\n";
		// resize image and save to destination directory
		system("convert -size $g1 $file -resize $g2 $dir/$file_lowercase");
	}
}
?>

If you want to try script, please download and save PHP code as resize.php. Set permissions to 755 and you can start resize.php like any script from the shell.

Enjoy!

This entry was posted on Wednesday, 15.10.2008. at 08:40and is filed under PHP. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.