Hi everyone! This is my first post here so I'm hoping to find some friends! Today I was out shopping and went to my local antique mall. In one of the booths I found a disney animation cel of madam mim in her dragon form from The Sword and the Stone. I was elated as I had never seen one in person before but had always wanted to start collecting them. The description on the tag said it was original but it had no certificate. The seller wasn't there at the time so I was unable to speak with them. However, it seemed in pretty good condition, there is a small section of paint missing in the lower right corner and it looks like it might be sticking to the backing in a few areas but other than that, it looks great. So I paid $150 for this and quite honestly, I don't know if it's a production cel or a reproduction or a fake. I also have no idea how I can go about finding this out. Any ideas?
Here are some pics:
Here are some pics:

