Alexander Reynolds says:
Moreover, tests of the "embedded sex objects" hypothesis don't pan out. It turns out that (a) people don't notice them unless they have been predisposed to (ie:"find the penis in the photo") and (b) whether or not there is an embed in the photo has no meaningful effect on the viewer.
Advertisers have found that such "artists jokes" as you call them are profit makers.
My friend Harry S. Hawk, who runs the Extropians list, works for an ad agency. I remember his reaction once to a news report about the nose on Joe Camel being a penis. He said, more or less... "yeah, I can see it now. The big guys are all in a meeting in the conference room, and they call in the artist and tell him 'It looks good, but frankly, it needs to be more, well, penis shaped. The nose, that is.'" No credible studies have ever shown that people notice subliminal messages. No credible studies have ever shown any of these "embedded images", either. If you believe they are there, it should be easy to find them. Take a scanner, scan in any newspaper image. Display only small subsets of the grey levels at once and your supposed subliminal messages should pop right out -- only you won't see a thing because they aren't there. Sure, sex sells -- look at any beer ad. But that is a different question. The notion that advertisers are going around deliberately incorporating hidden sexual imagery in an effort to boost sales has as much credibility as "The Protocols of the Elders of Zion". Perry PS By the way, none of this paranoia has anything to do with cryptography.