I used a psd file as a texture and it worked fine in IPR but not in final render. Have tested a few psd files with the same result.
From error log in terminal when running ./blender -d
pyrpr.CoreError: RPR call ContextCreateImageFromFile(<pyrpr.Context object at 0x12d39da58>, b'/Users/me/filepathHidden/file.psd', <pyrpr.Image object at 0x14a985828>) returned error code <ERROR_UNSUPPORTED_IMAGE_FORMAT<-8>> with error message: 'b'Unsupported image format //// FREXCEPTION : FILE=Cache/SimpleImageCache.cpp LINE=653 ERROR=-8 ////''
is something else
I should add that some files do not work in IPR either. RPR gets unstable after this and crashes randomly afterwards