Another thing worth mentioning is to stop watermarking your images. No one wants to see that "RICK JAMES PHOTOGRAPHY(C)" smothered across an otherwise pristine image. It cheapens the image and doesn't prevent theft. Watermarks are trivial to remove.
As to "stealing", it's the nature of the internet for people to use images they find online elsewhere for gratis, usually without attribution. I can completely understand if the copier claims they alone made the image, but these sort of claims can be and are disproven by the original author or other people who have seen the original work and are sometimes removed thanks to current copyright laws (at least in the USA.) Tools like TinEye or Google Images can also help find the original image.
However people do generally attribute images; those who don't (and don't claim the image as their own) are only "stealing" potential profit from the author, which can easily be prevented by either selling it to some group, like a newspaper or magazine, or not uploading the image to the internet at all.
Aesthetically, watermarks can look pretty gnarly, but this of course depends on the person and the watermark. For example, my current wallpaper is that of my favorite anime/manga and has only the compiler's watermark (not the author's) on it, one that is small and translucent. I don't mind it, because it's unobstructive, but if I put the image on Imgur, am I "stealing" from the author or just not giving credit where credit is due?
I look at unobtrusive watermarks like I look at the BSD license: you can use the image, but you're legally bound to preserve attribution, because the creator released the work for notoriety.