You use your web browser to upload photos to image hosts. If you sign up to Photobucket, it will take you through how to upload photos, then just follow the tutorial strewart posted.
Photobucket offers true URLs for pictures and that is what I use. It's free to use and pretty easy to figure out. So, I would suggest getting an account with them or similar online picture file organizers, upload any/all files that you would like to post here and on other forums, and use their link provided when available. - Lord Cedric