I saw a post somewhere over the last week or so but I am not sure if it was here or somewhere else so please forgive me if I am repeating, sorry.
I have made some animation avi's to use in my shell32.dll.
I extracted an AVI using reshacker then opened it in ULEAD GIF animator and changed the colour of it. Then, when I saved it it is 1.43 mb which is far too big. Does anyone know how these animations are compressed to make them so small?

you probably saved them using no compression, you can try indeo or something (gif movie gear can do it being shareware).
btw, i can't be sure if it'll work once you replace the file on shell32