It may be the print design background or work with ad agencies, but I use “FPO” in presentation proofs all the time.

FPO = For Position Only
“FPO” is used for temporary or unapproved images. The images are usually low-resolution comp images from the image resource (ie. istockphoto, Dreamstime, etc.). Its purpose is to show the proposed layout and receive client approval on the image before purchasing. When approved, the FPOs are replaced with the high-res images.

– Troy @ TLC