On photoshop, when the starting screen comes up - select new file, and type in 70 by 70 pixels.
You'll get the actual size - and then make the avatar how you want with whatever picture, and then export but MAKE SURE that the avatar size is under 8KB - cos that is the maximum.
And then upload and enjoy!
L O T U S
representing an unbreakable flower that survives under the hardest conditions and still thrives...