I have some questions.

I'll be uploading office chairs (and other office furniture).

Basically, there is going to be a lot of products and I wish to make it easier in the image file structure.

So ... Space Seating has sub-categories ... for example: Manager Chairs, Task Chairs, Reception Furniture, Drafting Chairs.

It is recommended to sub-categories the images folders to help with faster loading and such?

So, under the store's main images folder, so I do the sub-categorization there or do I have to do the sub-categorization under both the medium and large image folders?

Also
Do I still need to name the additional product images as (and I'll be using the product's model number for the images - just way easier):

13-7N1P3 (main image)
13-7N1P3_01
13-7N1P3_02

Thanks.