Testing the generation of Gif Image

I wrote in C# a method that generates a Gif out of multiple Bitmaps and I want to write unit tests for it. The problem is, I don't know exactly how.

I'd like to test the frame-rate, the number of frames, if it's looping, any of those if it's possible. So far I have the gif saved into a stream. I tried getting it as an Image but I don't find enough operations that I can do on an Image type that are related to the things that I want to test.

Any ideas on how to test the fields I specified or any other ideas on what I could unittest on a gif?