Or who want to post a picture more often, as has been the case numerous times. In either case they are just acronyms to alert the reader that the post contains a link to a photo.
Shel > [Original Message] > From: Mark Roberts > A few years ago some people started posting PAW (Picture A Week) > photos. One photograph shot and posted on the web every week. PESO > evolved as an alternative for people too busy or otherwise unable to > get a photo on line every week.
