I dont want to have my full images online. But I'm not sure how to protect them besides the small water mark. Can you implement an option for the biggest size allowed, or make a way to increase the watermark?
Maybe a percentage of the largest size over a certain amount. Say the image is 1280x1024, you could tell it not to allow anything bigger than 800x600 or perhaps 75% of the image, whatever it hits last? That way a small image that is 320x240 would be allowed to seen fully.
I'm not what would be best, just throwing ideas out there for the best image gallery app in the universe!