You can upload it to imageshack or some such, then use the Img button to display the image here. Click the img button (above the text input box when replying) and type the URL in between the open and close img tag and then the image will display.
If that doesn't work, you can also
create a support ticket and attach the file there (though you may need to zip it; I'm not sure that bmp or jpg are acceptable file extensions).