Photo Avatars - file type, compression, etc

[Iron Flatline]

Hi.

I've been playing around with a custom avatar, but I'm unhappy with my result. What file type should I be using? Gif, jpeg, bmp? Interlaced or linear? What kind of compression in Photoshop if Jpeg?

Any advice would be greatly appreciated. I've seen some crystal-clear avatars, and mine looks like a photocopied crime blotter. :meh:

 

[woodsac]

Well, 100x100 isn't much to work with and my current av probably isn't a good example, but I simply resize to 100x100 pixels and use the 'save to web' feature in PS.

By resizing first and saving as a jpg, it makes the image uploadable at 100% quality.