Hi Peach13! Understand the confusion for sure. The Pictures folder usually contains all of your pictures, not only your “PhotosLibrary” file, (Or iPhoto Library....the older version of PhotosLibrary), but a lot of times when you import pictures from an external device, (e.g. a phone or camera), depending on the app it’’s done with and the destination locations, a lot of times the photos will go into the Pictures Folder, (unless otherwise specified). The main folders in the home folder (your name) are just general folders where you can basically store any type of files you want, but it just makes it easy for organizational purposes.
If you wanted to, you could even create a “Photos” folder and place in anywhere, but in my experience, keeping it simple is the best way to go.
Hope that helps!