3 = 3, 4, and 5 digits. As I have low numbers of these pictures. Then it's 6 digits, 7 digits. 8 is when it gets messy, as there a lot of images that are 8 digits. So 8-1 means 8 digits with the starting number 1. 8-2 is 8 digits starting number 2. And so on. 9 20000+ is 9 digits or more with 20000 as the starting numbers. and so on.
It's cut down the number of issues i've had with images not loading. And it's quicker to load when checking for duplicates.
The custom folder is for the 'non-official' players added.