App to compare Photos libraries?

I’ve got three “photos” libraries on my Mac, and one is an old iPhoto library; the second is, I think, the Photos library that got formed when I upgraded one time; and the third is the one I primarily use.

I need an app or something that will compare them and help me see what’s missing from each, preferably without merging them all and running something like Gemini.

Any suggestions or ideas from the community?

Power Photos might help you.


I have used PhotoSweeper for years and it works very well at this AND thinning collections of many photos taken at the same event. For example, when you take a lot of pictures of kids doing cute things because they move so much but you end up with 40 pictures of them when 1 would suffice.


Thanks; that’s a good suggestion, too. With that in mind, what I’d really like to also figure out is an app or something that could take multiple photos of a similar instance and combine them for the best overall composite. I think that’s a little bit advanced for anything I can find right now, though!