Add watermarks with htaccess

Hi, I have written a short plugin that allows you to add watermarks with htaccess:

https://www.ads-software.com/plugins/add-watermark/

I tested it on some of my servers and found a .htaccess-Configuration that works in my cases. If you want to, fell free to test it on your server/configuration and give me feedback if the watermarks were added (and more importantly: If the cache wors or if every call is forwarded to PHP).