I created on my computer a new directory "Avatar", and thats where I am putting pictures used, and the avatars. Not sure which picture program you are using, or are comfortable with, but the pictures in the avatar need to be 60 x 60. To save space, I adjusted the properties of my pictures to 16 colors, instead of the 256 colors. The limit on avatars on this board are 20,000 bytes. My first attempt only accomidated 4 pictures of 5k, but by reducing the color setting to 16 colors, I was able to use all the pictures.

Once you have a version created and saved, you should be able to see it using most any browser.