Originally an internet photo meme used in news/blog posts to debunk overly excited individuals claiming to have pictures of some typically unbelievable event. This term is used to mock the ubiquitous douchebag Adobe Photoshop "gurus" who seem to be present and readily comment on every internet website where comments have been enabled, and claim to have so many years of professional Photoshop experience that they can spot a fake with a mere glance. In other words, there must have been equally annoying douchebag tapestry experts back in the middle ages who walked around pointing out fakery due to their extensive tapestry making experience.
"Dude, check out this picture of a UFO I took last night in the field across the street from my house!"
"Man, STFU. That shit looks tapestryshopp'd."