Make filenames visible (optionally) during slideshows.
Filenames last for the lifetime of the picture, and significant effort may have already been invested into giving a meaningful filename. File names are also portable, and captions may not be needed if the pictures have already been given meaningful file names.
Michael Skelmose commented
I have an extensive archive of historical motives, all numbered and described with meaningful filenames. It is the best way to keep track of the pictures on portable drives, in Explorer etc.
The Pictures itself does not tell much without the filename and it is not a way forward to scroll the info on several thousand Photos.
Why not make it possible to exchange the "Picture text" in the bottom of the Picture viewer with the filename.
not just slideshows but also in preview.