I did this by going into images in the tree, selecting files and editing the column.
I don't understand what this means, so I'll just add this comment, in case it helps...
There are two things that determine what files appear in any (Standard or Theatre) view:
1. Any files can be imported to the library. Which files are imported is determined by settings in
Import.
2. Any files
in the library may be displayed in
any view. Which files appear in a view is determined by the
Rules for file display settings associated with the view. Note that rules can be inherited from a parent view. So, for example, you might have a parent view where
[Media Type]=[Image] and then separate child views for photos, cover art, whatever. The
Rules for file display for those views would be whatever works to restrict the files to those that you want to see.
Unless your file system is perfectly organized, you're likely to have folders which you do not want to import, but which may contain some media files you would like to view in MC. Using
Drives & Devices, you can browse any folder on the system. Desired items can be selected and imported to the library—so they will appear in any view that includes them.