You could go license the image now and just send them a bill every month. But that's not really the ethical thing to do. But if you think it's going to be a problem, just write the company and explain your situation. If they're jerks about it, then get a lawyer to write them a letter.

I've never had a stolen image problem go past a lawyer sending someone a letter. When they get that letter, they tend to be more compliant in resolving the situation.