How do I delete multiple Photos from Macbook Air?

Hello, I have used 52% of my Macbook air's data and have been trying to get it cleaned up for my first day of College. Probably 26% of that data is practical applications I need, but I am having trouble deleting what I DON'T.

Back to the topic of the question, I have Photoshop elements 13 installed to my Mac and it seems to have made multiple files for same pictures (two files with same picture). So I am having difficulty deciphering which files contain the photos I need. When the photos are imported into Photoshop, I will assume the photos are read from a "Master File" and not from the application itself, are the photos read from a new file or the original file the Photo(s) were imported from. If a new file is made, which is safe to delete, the new or the original?

As kind of an extra question, do you think it would be a bad idea to delete the Photos application? I hardly use it and it seems less organized than Photoshop and iPhoto.



Thank you.