styles of video back covers

[minor muppetz]

Has anybody noticed that on the back covers of many videos released in the 1980s, there seemed to be a consitant style for how the pictures were put out depending on the company?

here are some examples:

Warner Bros: all videos from this company had either two pictures or one.

Disney: it seems like all back covers had one big picture, at least on videos of animated films, and that picture was mostly the entire back cover, with text printed over it.

CBS/ Fox: all videos had two pictures on the back.

Playhouse Video: all back covers had three pictures.

Random House: all videos didn't have any pictures on the back covers.

Paramount: I think they all had only one picture on the back covers.

Does anybody know when it started to become common for video companies to not have a specific format for how the covers were put out?