will tell you for most formats what version of the delegate you have.
JPEG* JPEG rw- Joint Photographic Experts Group JFIF format (90)
JPG* JPEG rw- Joint Photographic Experts Group JFIF format (90)
For some reason your tmpRGB.cache file is missing?
tmpRGB.mpc means use the first frame/page/layer of the file. tmpI.mpc was separated into its R,G,B channels and save in tmpRGB.mpc as 3 separate images. The [X] identifies which image (channel) stored in tmpRGB.mpc to use.
I do not know Cygwin, but convert.exe is the Windows version of convert and not the unix version you used. Perhaps this is just how IM puts out that error on Windows even if in Cygwin.convert.exe: unable to open pixel cache `./AUTOTONE.8608/tmpRGB.mpc': No such file or directory @ error/cache.c/OpenPixelCache/3711.
convert.exe: unable to persist pixel cache `./AUTOTONE.8608/tmpRGB.mpc' @ error/mpc.c/ReadMPCImage/944.
convert.exe: no images defined `./AUTOTONE.8608/tmpT.mpc' @ error/convert.c/ConvertImageCommand/3230.