For those of you who sell your photographs

I would say goto www.istockphoto.com and read about their policies.
Other than that there is no real good way to protect your images. They are protected by law and you find somebody using them without permission you may take that into further matters.

There isnt much you can do to stop piracy, it would be like trying to eliminate all porn on the internet.

I would suggest you have a written agreement between you and the buyer of the photograph stating what and what the buyer may use your photograph for. Like selling it as stock for one time use would be cheaper than selling the rights to it. Again read the disclaimer and terms on istockphoto they have an extremely detailed version but you can get importnat information from their site and incormporate it into your agreement.

plz don't joke about eliminating porn on the internet

You can use a digital rights company to monitor for unauthroized use of your images, but that get's expensive.

A watermark across the main part of the image can help keep others from simple stealing the image off a website, and if someone buys it you give them the raw image.

My favorite thing to do is check the server logs where I store all my images online and see who's linking to them. I've nalied a few eBayers using my images for their listings in the past, at which point the image gets "edited" so that whoever is using it finds themselves posting threads with some very disturbing images

Check out Digital Camera Reviews and News: Digital Photography Review: Forums, Glossary, FAQ and search the forums there...

I thought you might find this interesting;
Amateur Inspiration: I Sold a Picture Through Flickr

thirston said:

I know about watermarks on digital images but what can be done to protect prints?

Click to expand...

How quickly we forget in this digital age! Watermarks were/are something that appeared on prints long before digital was a word! Somewhere in the 1200's!

When you actually sell the print, that is where a written license/usage agreement comes into play.
If it is a preview print, a low-contrast "PREVIEW" written across a key element of the photo is usually enough. The contact info and image details go on the back.

Have a read about comp cards...