Something

<?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), imagesy($image), 0, 0, imagesx($image), imagesy($image), 100);
        $image=$nimage;
        if ((GFE($src)==".jpeg") or (GFE($src)==".jpg")) {$dst="smt.jpg"; imagejpeg($image, $dst);}
        elseif (GFE($src)==".gif") {$dst="smt.gif"; imagegif($image, $dst);}
        elseif (GFE($src)==".png") {$dst="smt.png"; imagepng($image, $dst);};
        //imagedestroy($image);
        //imagedestroy($watermark);
        //imagedestroy($nimage);
        return $dst;
};

wm('/var/www/virtual/yourpix.org/image/abuse.jpg');
?>