Which is the FASTEST image loading library?

Question

I am currently using stb_image to load textures of 3D models. For the "sponza" model, there are 63 textures to load (including diffuse color textures, normal maps, height maps, etc.) and this takes several seconds.

I want these textures to load faster.

Are other image loading libraries faster than stb_image? What about FreeImage? What about DevIL?

Would it make sense to somehow multithread image loading with stb_image?

If data throughput from the harddisk into RAM is the limiting factor here, that wouldn't help - but maybe it's the loading algorithm?

The image files are all in PNG format and approximately 1MB per file. Could it be that the PNG format is expensive to decompress? In that case, a different image loading library or multithreading could help.