To post a photo here in the forums, it first must be publicly available for the Internet to see. Some have mentioned ImageShack, but there are lots of "image hosting" services out there if you do a Google search for them. Once you upload your photo to them, you'll get a permanent URL link to them, like http://imagehack.com/etc/foo/blah.jpg which you can link in a forum post using the [img] tags that others have mentioned