Force images to be square.

square-image.php

<?php

/** 
 * Parameters
 * image = URL to original image
 * size = The size of the square (e.g. 300)
 **/

header("Content-Type: image/png");

$image = isset($_GET['image']) ? $_GET['image'] : null;
$size = isset($_GET['size']) ? $_GET['size'] : 300;

if($image && $size) {

	$name = basename($image);

	// Create new img
	$img = imagecreatetruecolor($size, $size);
	imagesavealpha($img, true);
	$color = imagecolorallocatealpha($img, 0, 0, 0, 127);
	imagefill($img, 0, 0, $color);

	// Get existing image

	$imageString = file_get_contents($image, false, NULL);
	$src = imagecreatefromstring($imageString);
	$width = imagesx($src);
	$height = imagesy($src);

	$y = $height != 300 ? 300/2 - ($height/2) : 0;
	$x = $width != 300 ? 300/2 - ($width/2) : 0;

	imagecopy($img, $src, $x, $y, 0, 0, $width, $height);

	imagepng($img);

}