I don't know if this is specific to pmp-art.com, but we have a Photo Album icon on each gallery in the Gallery list.
I'd expect that clicking that Photo Album icon would add the entire gallery to a photo album of choice, but in fact, it adds only one image from the gallery. When I tested it it was the oldest image in the gallery.
If the system is not intended to be able to add an entire gallery to a photo album, then I don't think it should be possible to have that icon on the Gallery list.
updated by @lornawebber: 10/07/20 03:12:09AM
JAMROOM
