How I can have an avatar?

[Devid_777]

Hi to everybody!
I'm a "fresher" here.
I'd like to have an avatar, (like other "forumers"). But I don't know how to do this. ;-(
Could you, please help me. Does anybody know where to download it?
Or if I have a large picture, is it possible to make it smaller, and suitable for the forum?
By the way, what it the limit size, in pixels and kb?

Thanks in advance..