At this time, we don't allow attachments. Here's how to post an image instead...
Upload it to some hosting site...either your free gallery space here at BP.net, or a hosting site like Photobucket. Then take the image's location URL and place it between the [IMG] tags... something like this:
[IMG]http://www.hostingsite.com/account/directory/filename.jpg[/IMG]
Most such sites, including our gallery or Photobucket, include the [IMG] codes that you can copy directly without having to worry about figuring it out yourself.