Hi AKSnake,
As long as the image is less than 102400 bytes you can just use the "Attach file" box and browse your PC for the file. (You can attach other file types such as "Zip" files this way as well).
To attach a larger image/file you need to first load the image onto your webspace (Most ISP's give you some free).
Then check the "Forum Rules" at the bottom of the "Reply/New post" page and click on the "IMG" link for a full explanation of what to do next.
Note... the Attach file option keeps the file available for ever on the BBS. The "IMG" tag is only a link so if you later delete the file from your webspace the image will disappear.
TTFN
snafu