This post at discuss 5 methods that can prevent it. The post might seem a bit old (it’s from 2005) but these methods are, if not 100% effective, still the best.

I’ve tried some of these methods, but some are quite annoying to be used, your site ends up getting a bit crippled, slower and it might not even work. Javascript for example and their pop-up messages like “COPYRIGHTED MATERIAL, DO NOT USE WITHOUT PERMISSION!!!” can scare some people off, but anyone a bit more clever knows how to bypass that and save the image anyway. The warnings in these messages are valid though.

I’ve learned from experience that the best isn’t to build big walls and stuff, but when and if some stealing episode ever happens, go trace whomever did that instead of punishing all your site’s visitors. It might be easier this way, sometimes a good traffic analyzer tool for your site can help a lot, even the free ones, mostly when it’s a case of bandwidth theft (hotlinking).

My method of choice now is just a plain simple watermark, placed carefully to not ruin the image’s aspect but also carefully placed in a region of the image where a cropping to get rid of it would get weird results. Again, it’s not 100% effective, there are people that have used even these watermarked images from places like without even bothering about the big watermark right in the middle of the image so they might even use the image from here “as is” too. This is not 100% bad, as if the watermark is preserved, it’s kind of an advertisement (for free) as well.

Regarding photography: I think with the ability to read the EXIF data of a file it’s sometimes easy to track down people that just copy the image(s) without much thinking, but I’m not sure how easy it would be to edit that kind of data and pretend that it’s your image.

As it says as a conclusion in the article, these methods can’t fully prevent someone from stealing your work. But it can sort of make the “lazy thieves” go away, which is the biggest part of them all. If one really wants to steal your content for whatever reason, sometimes they can do wonders to achieve that…