I don't see how taking someone as a mascot is insulting to that person. It's not even a depiction of Siddhartha Gautama, anyway -- it'd be more analogous to a picture of a Dominican monk than of Jesus.

Besides, the Buddha was a very smart guy, and much-admired, but that doesn't mean his image need be jealously guarded. I don't see the harm in a little irreverence -- if anything, light-hearted treatment of idols serves as a helpful reminder that nothing should be taken too seriously... can you explain why, in this case, it provoked the reaction in you that it did?