I use virtuemart. There are a lot of images about the products. But this images come from a php file(imgtag.php), so I can't force the browser with this code to take the product images to the cache:
<FilesMatch "\.(flv|gif|jpg|jpeg|png|ico|ttf|eot|swf)$">
Header set Cache-Control "max-age=2592000"
</FilesMatch>
Example for product image URL:
How can I do this?