[Feature request] Export image with its name rather than just the GLTF's name + number about sharpgltf

[vpenades]

This is not as trivial is it might look.

The reason because the library renames the images is because there's case scenarios (embedded images) where the texture file names are lost, and the library needs a unified way of handling texture names on export for all cases.

In fact, the code line you highlighted, and depending on the context, there is no guarantee to have texture file names at all.

it is doable for the use cases when texture names do exist, but it would require a case by case solution.