Mine

<?php  

function wm ($src)
{
function GFE($filename) {  
    $ext = strchr($filename,"."); 
    return $ext;  
}  
	
$watermark = imagecreatefrompng('watermark.png');
$watermark_width = imagesx($watermark);  
$watermark_height = imagesy($watermark);  
$image = imagecreatetruecolor($watermark_width, $watermark_height);  
if ((GFE($src)==".jpeg") or (GFE($src)==".jpg")) $image = imagecreatefromjpeg($src);
elseif (GFE($src)=='.gif') $image = imagecreatefromgif($src); 
elseif (GFE($src)==".png") $image = imagecreatefrompng($src);
$size = getimagesize($src); 
$nimage=imagecreatetruecolor(imagesx($image), imagesy($image)+$watermark_height);  
$dest_x = 0 ;   
$dest_y = $size[1] ;  
imagecopymerge($nimage, $image, 0, 0, 0, 0, imagesx($image), imagesy($image), 100);  
imagecopymerge($nimage, $watermark, (imagesx($image)/2-$watermark_width/2), imagesy($image), 0, 0, imagesx($image), imagesy($image), 100);
$image=$nimage;
if ((GFE($src)==".jpeg") or (GFE($src)==".jpg")) {$dst="smt.jpg"; imagejpeg($image, $dst); imagedestroy($image);}
elseif (GFE($src)==".gif") {$dst="smt.gif"; imagegif($image, $dst); imagedestroy($image);} 
elseif (GFE($src)==".png") {$dst="smt.png"; imagepng($image, $dst); imagedestroy($image);};  
echo "<img src=\"".$dst."\" width=\"".imagesx($image)."\" height=\"".imagesy($image)."\" />";
imagedestroy($watermark);
imagedestroy($nimage);
};

wm("abuse.jpg");
?>