Link? Can't find it

hello

you can do it yourself with some simple coding (well perhaps not that simple :-) )

but there is a reason why it's not done : there is no simple and global function to know witch image represents an album, because perhaps all your photos are public but it is not the case of everyone
it would require additional computing to know what would see a guest user (practically, visitors from twitter/reddit are guests for your gallery)

it's a technical part of Piwigo witch needs to be improved :)