An amusing meme on the Internet is the concept of “bubble porn”, also known as “Mormon porn”. The idea is to take a photo of someone who is scantily clad, but not nude, and mask out the clothing, leaving only bare skin exposed. The result is that the person in the photo now looks to be naked.
This phenomenon is actually a manifestation of Gestalt theory, specifically, the principal of closure, the property of emergence, and the principals of continuity and past experience. In psychology, there are several principals/laws/properties of the Gestalt theory of perception. There is no definitive set of Gestalt principals, and the theory itself is debated, but below are a selection of properties. Some of them are similar while some are overridden by others. In general, they cause things being seen to be perceived as units. Most of these are for visual perception, but proximity also works in time. That is, when two things occur close to each other, they are perceived to be connected, hence the perception of one thing causing another even if it did not.
In the case of bubble-porn, by masking out the clothing, the brain tries to fill in the blanks with what information is available, and since the information available is the surrounding skin, and since we have experience with what bodies look like, the mind perceives the person as being naked under the masks. As if celebrities didn’t already have enough to worry about with fake nude photos (and as of 2017, AI-generated fake videos).