Should I be concern when posting my photos on FM or any other websites like FM on people copying my work and using them elsewhere? Is there a place I can copyright my photos?
I think where ever you post them there's always the risk they will get stolen. Other than putting your copyright over the image (and never posting the original) I'm not sure what else you can do.
Just hope that anyone who steals it uses it for something you or your friends will see.
Any time you post a photo online, it can be copied. In fact, by the very way that web browsers work, when it is displayed on someone's computer, it is first downloaded to their hard drive.
Also, your images are automatically copyrighted (Assuming that you're in the US) when they are first created. To sue for monetary damages if your copyright is infringed, the photo does need to be registered with the US copyright office.
The best protection that I have found is to just post pictures in a low enough resolution that decent prints cannot be made. Don't upload full resolution photos to sites like Flickr, and if you do, make sure that only contacts can download the full resolution.
In my opinion, watermarks are distracting, and take away from your photos. Javascript that attempts to disable right clicking on web pages is not effective at all, and only annoys people.