In 1999 Disney recalled 3.4million copies of ‘The Rescuers’ because of this:
The film was made in 1977, and a picture of a topless woman had been inserted into the film post production. It had gone unnoticed until the development of VHS and the ability to pause ‘frame by frame.’
Consequently, when word of the ‘objectionable background image’ got out, people rushed out in their thousands to buy the film. Marketing genius? Possibly. Funny? YES!