Dear 100 Hour Board,
I know that some Disney cartoons (Lion King, Little Mermaid) have inappropriate drawings in them that are disguised. What other Disney movies have these and WHY do the artists feel the need to cause controversy to these movies?
Actually, most of the things you're citing are just rumors, myths, and legends, or are at the very least incredibly ambiguous...at least if you take Snopes.com at its word (which I tend to do). In fact, the only risqué thing ever confirmed in a Disney movie was from The Rescuers, in which there were two frames where a topless woman could be (hardly) seen in the background. And that, claims Disney, was done in post-production, not by any of the animators.
Don't believe everything you hear.
The only other film I've heard rumored to have inappropriate frames is Who Framed Roger Rabbit, which seems to have more truth to the rumors than the Lion King and Little Mermaid rumors you reference.
As for how these rumors come about, it is not unheard of for animators to amuse themselves by slipping unexpected and/or inappropriate drawings into their films. This practice has been seen less and less since home video players which allowed frame-by-frame viewing have been introduced (before at-home frame-by-frame viewing was a possibility, nobody would have ever seen these frames).
However, as the links Claudio provided explain, often the viewer is convinced they see something they don't because they've been told it's there.
"Know" is a pretty strong word. The Lion King one is debatable and, like a Rorschach test, says more about the viewer than the film; the Little Mermaid one is totally wrong. The only obviously deliberate lewd addition was in The Rescuers, which was discovered by Disney, which promptly recalled 3.4 million copies of the video. There is also some controversy regarding Who Framed Roger Rabbit.
As for why, well, Snopes suggests that animators amused themselves by inserting racy content that was only a few frames long—far too short for audiences in a theater to ever be able to see. Though it was certainly inappropriate, it was also unnoticeable and therefore harmless to audiences. However, with the replay, pause, and frame-by-frame abilities of home video, these bits are accessible to viewers who look for them. But only the animators can speak for their motives.
Waldorf and Sauron (who apparently wrote this answer at the same time as Humble Master and Claudio)
Oops. Missed that one. Still, Heeyah!, Snopes only gives that one an "undetermined."
Hi, it's me again. I just wanted to touch on the motivation aspect of your question, which I didn't do justice to in my first response. I think that, generally, the motivation for an animator to put in anything inappropriate is to amuse themselves and tickle their admittedly juvenile sense of humor. As has been stated, none of the so-called controversies really has any affect on the viewer (subliminal messages don't work). Most likely, they're bored of drawing the same thing over and over (which they knew was in the job description, that doesn't mean it wouldn't get monotonous). It's possible that to break the boredom they add something that makes them chuckle in a juvenile sort of way, but that in no way is meant to subvert the morals of generations of children that watch animated films.