I'm sure there is. Plenty of sites do it, but it's complex work with the GD library. You might be able to find an open-source PHP class that does it for you.

Hey Fuzz10,
I am struggling to implement it into my website... I am wanting to make it add the watermark to all the large images (not the thumbnails)

Do I add that function into the page control for the gallery page? or into the gd.php file?
How do I call it on the page?

Thanks HEAPS for your help!

If you're too busy to explain it, if you just sent me the pages involved I'll be able to work the rest out me@bradydyer.com

Cheers!

can anybody shed any more light on this?
im struggling to work out where to actually put the code.

im working with Uncle Cheese's Image_gallery.

do i apply the watermark when images are UPLOADED via the CMS, or is it when they are RENDERED?

do i do something like this?

   public function Watermark(GD $gd) {
   // Read the watermark picture
   $watermark = imagecreatefrompng($URL . '/themes/Ace/images/watermark.png');
   $watermark_width = imagesx($watermark);
   $watermark_height = imagesy($watermark);

   // Read Full size Silverstripe image
   $imageToWatermark = imagecreatefromjpeg($this->URL);

   // Calculate sizes
   $size = getimagesize($this->URL);
   $dest_x = $size[0] - $watermark_width - 5;
   $dest_y = $size[1] - $watermark_height - 5;

   // Do transformations and save image in assets
   imagecopymerge($imageToWatermark, $watermark, $dest_x, $dest_y, 0, 0, $watermark_width, $watermark_height, 40);
   imagepng($imageToWatermark,$webroot . $this->filename . "_watermarked.png");
   
   // And this is the trick ;-) Create an object Silverstripe can work with....
   $GDoutput= new GD($webroot . $this->filename . "_watermarked.png");
   return $GDoutput;
   }