There are probably (definately) better guys to help than me but here’s my attempt:
Save the pic on your computer (My Documents or My Pictures).
Do your regular post thing and then click CONTINUE. Be sure the “I want to preview my post and/or attach a file” box is checked by the CONTINUE button.
When you hit continue you will see your post… look down a bit and you will see “You may attach a file if you like (no bigger than 100000 bytes please). ” and a BROWSE button.
Click the BROWSE button to look for your pic (of course you have to remember what you named the pic in the first place). When you find the pic you want to post, double click on it and it should enter into that browser bar.
Click CONTINUE again and it should be done.
I hope this helps. If it is not correct, just wait. Someone wiser than I will be along soon.
Good Luck! – Wade