you click on 'Edit my Profile' up near the top right hand corner of the TR web page - whent hat is open, you click on the button 'Edit Profile' on the left hand side about a quarter of the way down the page, whent hat opens the top data entry box is where you eneter the URL of where your photo is stored on the Internet. Then save and back out saving.
Most people place their photo on their web site somewhere, if no web site (most ISPs will host a basic one free), you can store it at places like MySpace, Clickr, PhotoBucket (as TT said), or get a free mail account with a linked basic web site capability - some offer them, others offer the opportunity to download your photo to the blogger page they offer.
Worse case scenario is you contact a TR member you feel friendly with, send them the photo and ask them to put it up for you. Most of the people are nice enough to do that, repeat MOST not all.