DS 6.x can generate WinPE ISO's - you could generate a standalone WinPE ISO (no network connectivity) and use some utilities like WinISO to insert your image file and rdeploy into the ISO, then use another utility to copy the ISO to a USB key and make it bootable. I can't remember off-hand what utilities do that, but I know I've done it before.
If you can't get the USB key to boot, you could boot to a WinPE standalone CD to boot then access the image from the USB key.