I'm a photography/video editor, but I work for myself and I'm contract labor for several magazines and websites.

So, they pay me to do whatever they want, and anything I do on the clock is considered their property. Now if I created an image at home, then suggested they use it, but they refused. Then I saw them using it a year later, I would then take legal action (or tell them to pay for its use).

I've had pictures I took appear in magazines I've never worked with before, and every time I call them and tell them to pay up (and they do).

People and companies are so afraid of lawsuits these days you probably could get some money out of it, but personally, I don't think you have much of a case.