Goal: Display set of images across all galleries based on a query using tags, categories, author name, upload date, etc.
Perhaps even EXIF data
Background: For the Astronomy Club, to list images of certain category across all members galleries is required.
(shared gallery not a nice option, per Author a individual gallery would be used)
E.g. lunar eclipes: Show all images of category "Moon", "Eclipse" and EXIF create Date "15 June 00:00-23:59" (full day or spread over many days)
Another use case is that you would like to list all images regarding "Galaxies" of a certain users (in a blog or page)
and so on.
Any hint if this is already possible is highly appreciated.