GD Resize Crop

if(isset($_GET['url']) && $_GET['url']!=''){
  	$tm = explode("?",$_GET['url']);
	if(isset($_GET['size'])) {
		if($_GET['size']=="tiny") {
			$dwidth = 85;
	    	$dheight = 57;
		}
		else {
			$dwidth = 600;
	    	$dheight = 460;
		}
	}
	else {
		$dwidth = 500;
	    $dheight = 250;
	}
  	$picurl = urldecode($_GET['url']);
    $info = getimagesize($picurl);
 
    list ($width, $height) = $info;
	if ($info['mime'] == 'image/jpeg') {
  		$source = imagecreatefromjpeg($picurl);
  	}
  	else if ($info['mime'] == 'image/bmp') {
  		$source = imagecreatefrombmp($picurl);
  	}	
	$source_aspect_ratio = $width / $height;
	$desired_aspect_ratio = $dwidth / $dheight;
	if ( $source_aspect_ratio > $desired_aspect_ratio ) {
		$temp_height = $dheight;
		$temp_width = ( int ) ( $dheight * $source_aspect_ratio );
	}
	else {
		$temp_width = $dwidth;
		$temp_height = ( int ) ( $dwidth / $source_aspect_ratio );
	}
	$temp_gdim = imagecreatetruecolor( $temp_width, $temp_height );
	imagecopyresampled($temp_gdim, $source, 0, 0, 0, 0, $temp_width, $temp_height, $width, $height);
 
	$x0 = ( $temp_width - $dwidth ) / 2;
	$y0 = ( $temp_height - $dheight ) / 2;
 
	$thumb = imagecreatetruecolor( $dwidth, $dheight );
	imagecopy($thumb,$temp_gdim,0, 0, $x0, $y0, $dwidth, $dheight );
 
	header('Content-type: image/png');
	imagejpeg($thumb, "", 100);
}