This is a cel of Arale from Dr. Slump. I've been informed which part of the series this cel came from! HON in Hong Kong wrote to me and told me the following:

"On your webpage, you say you don't know where the picture of Arale of Dr.Slump comes from. In fact, it comes from a movie shown in the summer, 1994 in Japan. Arale is playing around in the ghost hotel. I know it because I've just seen this movie in rental video tape and recognise her clothing. Dr.Slump has been much well-known in HK that the TV anime rebroadcasts again and again."

Thank you SO much!!
I got it from David Vernal through Marisa Price. There's tissue paper attached to the cel and I can't remove it, but the lines crossing the cel are folds in the tissue paper and are not flaws in the cel. The dark blotch at the bottom is apparently an airbrushed shadow. The outline of it can be seen on the pencil.

What an awsome cel of Arale and Supaman! I got it from Kev's Cel Page. It's stuck to the pencil, but very cute!