Add New Product - Way to drill down into Image subfolders?

I have an enormous amount of images to work with in converting an existing non-cart site to Zen Cart. I currently have a main image folder and subfolders within such as:

images/coats/series200
images/coats/colors
images/beds/style1
images/beds/style1\colors

In trying to reproduce this image folder structure in Zen Cart, I find that when I go to "add a product", the image "Upload to directory" pulldown only lists one level of subfolders underneath images. So, I am only able to pick the coats folder when I really need to drilldown further and pick coats/series200

Is this by design that Zen Cart only works with one level of subfolders underneath Images? I haven't found anything in the Tutorials section specifically addressing this. I really would rather not have hundreds of images in one level of folders. If I have to then, I'll have to work with it but, just trying to find out if there is a way to get the subfolders to list when adding a new product. Thanks.

Except for the folders /medium and /large, the cart only works with the one level of subfolders.
You'd need to some modifications on both the catalog and admin sides of the store to modify this functionality - changes on the catalog side could use the override system but on the admin side would overwrite core files.