stb_image appears to have support for plug-in SIMD implementation(s) of the idct and ycbcr->rgb conversion operations, which take majority of time when loading jpeg files. Looking at the code behind STBI_SIMD it's pretty clear this code has actually been used somewhere.
However, either the implementations have been proprietary, or my google-fu fails me, as I haven't found any public code that uses this interface.
My needs would be for the x86 platform only (at this time).
Is there any open source that uses this interface?