GifSplitter can split gif animation to image file(s) list. Then, you can select any frames of the gif animation, and modify them as you like.

Also, GifSplitter will create a .mifl file which can be used in Magic ASCII Studio (http://www.xoyosoft.com/mas). So, with the help of GifSplitter you can make ASCII Art Animation directly from gif animation file in Magic ASCII Studio now.