Apply Watermark image into Product Image of Virtuemart

Problem: When Creating an shopping website, we would like to apply a watermark image - logo and website name - on every picture of products. It is seem easy by this way: use an watermark program to apply icon on product picture, then upload that picture on hosting. Take a long time if you have over 50 products.
I want to do this work automatically, It means watermark picture will be applied in to all picture (old and new) of website

Solve: I do this work on Joomla 2.5 and Virtuemart 2.0. But I think it is comfortable for every happen load and show Image.

• Step 1: Create file .htaccess on folder contain image, with Virtuemart 2.0, this folder is <your_domain>/images/stories/virtuemart/product.
  
  RewriteRule ^(resized)($|/) - [L]
  RewriteEngine On
  RewriteCond %{REQUEST_FILENAME} -f
  RewriteRule \.(gif|jpeg|jpg|png)$ watermark.php [QSA,NC]
• Step 2: Create file watermark.php at same folder of .htaccess with content:
  
  
  <?php
  // watermark.php
  // Path the the requested file
  $path = $_SERVER['DOCUMENT_ROOT'].$_SERVER['REQUEST_URI'];
  // Load the requested image
  $image = imagecreatefromstring(file_get_contents($path));$w = imagesx($image);$h = imagesy($image);
  // Load the watermark image
  $watermark = imagecreatefrompng('watermark.png');$ww = imagesx($watermark);$wh = imagesy($watermark);
  // Merge watermark upon the original image (centred)
  imagecopy($image, $watermark, (($w/2)-($ww/2)), (($h/2)-($wh/2)), 0, 0, $ww, $wh);
  // Send the image
  header('Content-type: image/jpeg');imagejpeg($image,null,95);
  exit();?>
• Step 3: Create an watermark.png with transparent background and upload to that folder.

Done.

Now you can test all image file in folder <your_domain>/images/stories/virtuemart/product have watermark if you call them on your website

Note: the code line RewriteRule ^(resized)($|/) - [L] in .htaccess file ensure that all thumbnail file in resized folder will be not watermarked. If you want to watermark on both thumbnail and large picture, you can remove that line

Demo