OK, here goes - instructions received from Ballerina quite some time back:
Save the pictures you want to your computer picture file.
Go to http://tinypic.com/index.php
Click on "Browse". That should take you to your computer's picture file.
Click on the picture that you want to use on TBC. You may have to also click on "Open" after you select the picture you want. (I did have to click on "open" for this to work. Karin)
It will then take you back to the tinypic web-site.
Click on "Default", and then click on "Message Board (640 x480)"
Then click on "Upload Now"
In an effort to do away with spammers, tiny pic will ask a question and then ask you to type in the answer. After you do that, click on "Upload Now".
Highlight "IMG Code for Forums and Message Boards". Then hit Control + c to capture the link. Then place it where you want it in your TBC forum message and hit control + v.