I'm working on the graphics part of my website and I'm using 150px x 150px jpg tiles repeated on the pages as backgrounds. Different ones for different pages. I also using jpg images as buttons for the links. Again, different ones for different pages.
And I've got a choice. I can put all the background tiles and button images in one folder, and all the pages in a second folder, and link the pages in the second folder to the backgrounds and buttons in the first one.
Or I can create a separate folder for each page, and put the background tile and button images associated with a particular page in the folder with it.
As far as the site functioning, either will do, but I find the less folders the better.
I associate the image names with the pages and by function. imagefredrt, imagefred270, imagefred600 so they will appear together in a directory listing. This also allows to see any inconsistency in your scheme.