Get a free account at www.photobucket.com
and sign into your new account there.
Click the "BROWSE" Button on thier page and find the image on your computer. Select it, click ok and "SUBMIT". That should put the image up in your Photobucket account.
Look under your image for its IMG <address> /IMG tagged line you can copy. Highlight that line, ctrl-c or right click and copy.
Come to this forum, start your message and right click and paste that IMG <address>/IMG line back in to this forum and preview your message. The image should show up.
Note: I left [ ] off of the IMG and /IMG tag but they ARE required to work here. If I had put them in though the forum would not let me show you the example. :P