The extra backslash is there because that address is for an entire page. That's why it works as a link.
http://imageshack.us/photo/my-images/80 ... 021bl.jpg/The actual image location needed for the image tags is (minus the greater than/less than signs):
<http://img801.imageshack.us/img801/9519/picture021bl.jpg>
Add the image tags to the above and...
Now in the picture, why the board is displaying the garbage text. I don't know. Since everyone isn't displaying that, the problem would seem to be on the user's end. That's all I could say for certain. I would guess the computer isn't recognizing the display text font correctly. The first thing I'd try is switching to one of the other board displays, one of the more "plain vanilla" ones like prosilver. Go to User Control Panel, Board Preferences, and My Board Style and select one of the other board styles. Restart your browser if necessary.