Sorry to take up so much space, but I have a tip for you. A friend of mine who is a professional photographer has been posting darling pictures of her baby girl to her blog and Facebook, and recently found out that those images have been used by others (whether for commercial use or not, I'm not sure). Somebody sent her a link (which I saw and snagged) about an artist/blogger who was in a similar situation.
I'm not trying to incite panic, but I thought it'd be helpful to read about how this blogger came up with solutions on how to protect your online images. Watermarks and shrink-wrapping seemed like the best ideas to me-- I plan to try those in the future.
Fair warning, the blog post includes a bit of colorful language, probably because the author is talking about their stuff being stolen. Here's the link: