I'm currently using Firefox v51, but have this issue across browsers. The pop-up window for the image gallery is very limiting. It only displays 8 images at once, and when you have 1000+ images, it makes it incredibly difficult to navigate and manage. Several other websites handle this better and I would love to see an update in the near future where it's full screen, you can tag photos, and organize them in folders. The organization of the media libraries on Flickr and Wordpress both come to mind as examples of good user interfaces.