All categories, description of them and some examples:
Publicity Still is a picture made on set where no part of the crew is seen, and actors are not posing to the camera. They look just as a capture of a moment of the movie. Screencaptures can be here too but only if they are official (if there's some not official one, is just a mistake of mod team, tell us).
Behind the Scenes are all pictures made on set that doesn't belong to the Publicity Still category because there's crew on picture, actors posing, green/blue screens not digitalized yet.
Pre-production are pictures of the work made on the movie that's not on set, that includes designs, blueprints, mockups, dress/costume, empty scenarios, make-up...
Promo shoot are pictures where usually actors and sometimes members of the crew appear clearly posing in a photoshoot, usually having plain coloured backgrounds or part of the scenario. These are usually the unedited pictures that are later used to make posters or other kind of promotional art.
Promotional art includes pictures of the actors highly edited, CG... For poster designs we approve only textless versions, only-title or very small texts. The line in case of doubts will be if they include dates of release and/or the typical copy text with cast/crew names and companies, those are just posters and for that reason, not allowed here.
Wallpapers are any official (and only official) picture made with the intention of being used as an screen background (for PC, tablet or smartphones). Remember, the wallpaper must be official as a wallpaper, any official picture cropped to wallpaper size is still an official (but modified) picture, but it's not an official wallpaper.
Lobby Cards were (there are lobby cards today but not that much) printed sets used in theatres to promote films (posters not included). They usually appear in sets of 8 pictures (though can be from 6 to 12) usually numbered that have some design unifications, like a frame containing a publicity still. There's too the title lobby card that leads the set and has a design similar to a half-sheet (horizontal) poster, and those are accepted in this page too as a part of the full set.
Publicity Still is a picture made on set where no part of the crew is seen, and actors are not posing to the camera. They look just as a capture of a moment of the movie. Screencaptures can be here too but only if they are official (if there's some not official one, is just a mistake of mod team, tell us).
Behind the Scenes are all pictures made on set that doesn't belong to the Publicity Still category because there's crew on picture, actors posing, green/blue screens not digitalized yet.
Pre-production are pictures of the work made on the movie that's not on set, that includes designs, blueprints, mockups, dress/costume, empty scenarios, make-up...
Promo shoot are pictures where usually actors and sometimes members of the crew appear clearly posing in a photoshoot, usually having plain coloured backgrounds or part of the scenario. These are usually the unedited pictures that are later used to make posters or other kind of promotional art.
Promotional art includes pictures of the actors highly edited, CG... For poster designs we approve only textless versions, only-title or very small texts. The line in case of doubts will be if they include dates of release and/or the typical copy text with cast/crew names and companies, those are just posters and for that reason, not allowed here.
Wallpapers are any official (and only official) picture made with the intention of being used as an screen background (for PC, tablet or smartphones). Remember, the wallpaper must be official as a wallpaper, any official picture cropped to wallpaper size is still an official (but modified) picture, but it's not an official wallpaper.
Lobby Cards were (there are lobby cards today but not that much) printed sets used in theatres to promote films (posters not included). They usually appear in sets of 8 pictures (though can be from 6 to 12) usually numbered that have some design unifications, like a frame containing a publicity still. There's too the title lobby card that leads the set and has a design similar to a half-sheet (horizontal) poster, and those are accepted in this page too as a part of the full set.