Yes, you absolutely do have recourse. Unless you signed a document explicitly providing permission for them to use your image then you could pursue a claim against them. And even if you did sign over rights for them to use your image, it would still be arguable in court if you were not suitably compensated for it.
Have a think about what is most important to you. Do you want the image removed, or do you want to be compensated for it? If the former, an email / letter to the school from you should suffice. If the latter, you'll need a lawyer. In all seriousness, you could be looking at a decent pay day for this. The general rule would be what would it have cost the school to hire someone else for that. A standard i.e. not famous model's feel could be a few 10s of 1000s of baht....
If you tell them you want it taken down and they don't, you could make a criminal complaint and / or pursue civil damages against them.
Basically, you have a lot of options. Think about what you want to do and then proceed accordingly.