don't they all work?
is your start9 on your network? any browser should be able to be pointed at any photo (or file) on your server. that's the whole point.
Discussion
For a ui that is going to let you look through and search all your photos. Specifically one installed on start9 itself. Are you saying I can install one on my Linus laptop and point it at next cloud for its backend?
it's a server. on your network. it comes with software so it can serve. depending on your security setting, and how you configure, you can browse with you Linux laptop. if you can't, what's the point?
Browse yes. But there are photo browsers that add features like search based on faces or tags or whatever, not simply serving me my files.