Function: image_resize()

<?php
function image_resize($image,$width,$height,$color=array(0,0,0)){
	if(@$size = getimagesize($image)){
		$newsize=array();
		if($size[0]==$size[1]){
			$newsize['width']=$width;
			$newsize['height']=$height;
		}elseif($size[0]<$size[1]){
			$ratio=$height/$size[1];
			$newsize['width']=$ratio*$size[0];
			$newsize['height']=$ratio*$size[1];
		}else{
			$ratio=$width/$size[0];
			$newsize['width']=$ratio*$size[0];
			$newsize['height']=$ratio*$size[1];
		}
		if($newsize['width']>$size[0]){
			$newsize['width']=$size[0];
		}
		if($newsize['height']>$size[1]){
			$newsize['height']=$size[1];
		}
		switch($size[2]){
			case 1:
				$input=imagecreatefromgif($image);
				break;
			case 2:
				$input=imagecreatefromjpeg($image);
				break;
			case 3:
				$input=imagecreatefrompng(image);
				break;
			default:
				$input=imagecreate($width,$height);
				imagecolorallocate($input,125,125,125);
				imagestring($input,2,2,2,'Wrong image type',imagecolorallocate($input,230,230,230));
		}
		$output=imagecreatetruecolor($width,$height);
		imagecolorallocate($output,$color[0],$color[1],$color[2]);
		imagecopyresampled($output,$input,0,0,0,0,$newsize['width'],$newsize['height'],$size[0],$size[1]);
	}else{
		$output=imagecreate($width,$height);
		imagecolorallocate($output,125,125,125);
		imagestring($output,2,2,2,'The image does not exists',imagecolorallocate($output,230,230,230));
		imagestring($output,2,2,15,'or is not reachable',imagecolorallocate($output,230,230,230));
	}
	imagepng($output);
}
image_resize('http://website.com/pic.gif',100,200,array(255,0,0)); 
/* de eerste waarde is de url naar het plaatje
    de 2e de breedte
    de 3e is de hoogte
    en de 4e de kleuren (in RGB) */
?>