I build my texture images in Photoshop, placing difuse, specular, normal, etc. in separate layers then saving them as individual files for use as textures in Blender. I'd like to share some of these and (assuming Photoshop format is undesirable) was wondering is there is another file format that supports layers that would be more accessible to the general public.

Why don't I just upload the individual files? I'm prepping some general purpose texture images of street signs but won't be using them anytime soon and am lazy and want to have to curate as few files as possible. This isn't a huge issue for me, but I may end up with a couple of dozen images with at least two layers each, and the less effort I have to put into it the more likely it is to get done :)