Are there any rules about including pictures or other things. For you that are more daring a tip. . Georgia has recently banned biker magazines because of the scanty clad ladies and not even semi-nude either. Poloroids are generally refused because the photo has a really small pouch where the developing chemicals were originally stored on each photo. When something in an envelope is deemed 'contraband' and then is refused the whole envelope is either sent back or trashed.
Some institutions make the inmate pay to have it sent back or else they just trash it.
Makes sense when you think about it, anything Godly placed before this system IS offensive and obscene. Food stuffs are generally refused as are most anything else of use to the inmate. I suspect it is to force the inmate into having to purchase all items through the facility's Canteen that has arranged a contracted monopoly to provide convienient store sized products and selection at resort town prices. Books and magazines usually must be sent direct from a publisher or commercial business. Even newspaper clippings can be refused if the facility considers it harmful to the security of the facility like a story of a riot in another prison or recent Supreme Court rulings.