Katie--

I'd add a copyright symbol, though I agree with Barb that it won't stop anyone. What's happening to you (if people are using the photo and text) is called "blog scraping," and it's extraordinarily difficult to to stop if it's happening overseas and out of reach of U.S. copyright laws.

In the U.S. you may have better luck. You need to send (or email) the offender what's called a "takedown letter." You can find samples online if you search for terms like "DIY takedown notice [or letter]"; "Sample takedown letter"; or "DMCA takedown" (which stands for Digital Millennium Copyright Act). It's easy to do and often works here.

There's a moral case for doing it because you HAVE the copyright even if you don't add the symbol. And if you don't put the offender on notice, it makes things worse for other writers for whom it the violation may matter a lot (for example, by depriving them of potential income). Silence encourages the violators.

Jan