Hello guys! This is my first post around here. I know some people do this, but I have no idea how to achieve it. Say I am selling a gallery online (100 pics). Can I save a small "mark" on the code of a random picture (which would be automatically placed when someone buys the set), which could later be used to trace whoever is sharing the gallery? Its what they call a hidden watermark.
How do you guys think this could be achived?
Thanks so much for your help!!!
- Monika