You should at least ask that they credit you as the origin of the work but at the end of the day it is probably not worth chasing. If it bothers you then don’t post your work… make people have to pay to gain access to your site. If there is no money being made by you or those copying your work then you are unlikely to get a huge amount through the courts… that is assuming they are in a country you can bring actions against.

I’d suggest you start putting watermarks through you images and perhaps feel free to copy their content, or ridcule them for what they are doing on public forums related to the area of interest. If there are any magazines that are pinching your work then definitely get a lawyer to draft an official looking document to scare them.

A guy on another forum I frequent managed to whip up quite a lot of energy against an American Computer Magazine that published an inappropriate photo. (The photo was part of an advert for a new game and showed a line of Russian soldiers holding the game… the black arm bands gave away the fact that the men were actually lined up in a ceremony commemorating those that had fallen in Chechnia and the things they were holding were not boxed of a SOCOM game, but the photos of their fallen comrades. The first reply was quite aggressive and threatened the guy for copyright infringement for posting the advert on the net, but as the original photo was also copyrighted with the requirement that it not be used in a distasteful manner they really didn’t have a leg to stand on.

Fair use of material on the web basically means that someone can post someone elses work for the purposes of critiquing it, or for the purposes of discussion… as long as they are not passing it off as their own work. Most of the time the best you can hope for is that they credit the original owner and maybe include a link to their site.

Actually going after them would be expensive and time consuming… and unlikely to make much difference.