How can I remove photo files
I have an external SSD via thunderbolt hooked up as my startup drive. The internal drive is used for some storage and another external drive is connected via USB. I have all my Photos libraries set up to save to the external HDD. However, I find that the Startup SSD still has a large amount of storage occupied by photos. The default user folder for the Photos library is empty. How to I find and remove these photos? They are probably already in the library saved to the external drive so I just want to delete them to free up space. Presently I have had trouble installing new apps because of this problem.
iMac, macOS High Sierra (10.13.6)