Picks photos and videos together in the Select mode (at least two files; each file's kind is read from its bytes): a carousel with a video child. Answers the post editor's handle.
Picks one photo in the grid (photo.file holds its bytes): reads its format and
dimensions, keeps it in the process's media pool and opens the post editor. Answers the
editor's handle.
Turns on the grid's Select mode and picks one or more photos (at least one, by type): a carousel. Answers the post editor's handle.
Picks one video in the post mode (video.file holds its bytes). The app takes it through
the creation camera and opens the Reel editor, so it publishes as a Reel. Answers the Reel
editor's handle.
Moves the mode selector to REEL or STORY (mode) and opens the creation camera. Answers
the camera's handle.
The actions of PostingGalleryPickerScreen: the methods you call on its handle while the screen is open.