Right now you select images from your kind 1 feeds to add to your gallery. (By going full screen, share -> add to gallery)

The other way would be to simply post images in the multimedia tab (in the middle) and these would automatically end up in the gallery and be synced across clients that use NIP68.
So kind 1 media (screenshots, shitposts etc) would not end in the gallery but those media files you chose to post in what Olas calls "high quality posts"