The little Pics are so called "Avatars" and a way to get such a Avatar can you find here

UR? i think you mean a URL that the adress of a webpage, or the adress where you can find (for exampel) an Avatar.

And, no. you cant upload pics from your Desktop, but follow the link above, there are some links to Websites with Avatars where you can choose one.

Das Ganze ist mehr als die Summe seiner Teile(Aristoteles)
Aber wenn man das einzelne nicht mehr beachtet, hat das ganze keinen Sinn mehr (Stone)