either you upload it to your web site.. or an ftp server.. or else find one on the web.. then just type in the url address like so http://www.blah.com/yourimagehere.jpg Let me know if you need help with that.. (web space etc).
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Palm Trees and Cedars Rock! Psalm 92:12 The [uncompromisingly] righteous shall flourish like the palm tree [be long-lived, stately, upright, useful, and fruitful]; they shall grow like a cedar in Lebanon [majestic, stable, durable, and incorruptible].
Yep, upload the picture (max 100x100 pixels) you want somewhere, and then where it says "logged in - your username" click on that. It'll take you where you can edit your profile. Go to the Avatar section, and use the drop-down menu to choose 'specify your own' (unless, of course, you just want to use one they have there). Under "Avatar URL", put in the url of the picture you've uploaded, and click "Save changes!"