Generate animated .gif from two images?

I was wondering if you can create an animated .gif from two images, so can you?

The images would be the same size so no extra conditions(?) there.

I'm having a live image being pulled from a website every so often, like 10 minutes, and I want to compile all the saved images into a short .gif file.

I could just get a program to do it for me, but what's the fun in that? I also need to be working on my image manipulation, because I have little experience in that.

I don't know of any built in functions for this in .NET. If I'm wrong, someone correct me. If there aren't, I would suggest using a third party library for conversion instead of rolling your own. If you really wanted to, you could check out the spec on GIF images and do the conversion yourself I guess.