In AMT 9.5 SDK(IntelAMT126.96.36.199Gold) there is note related to img/iso file redirection for Linux
When working in Linux, Redirection is supported with physical disks only. There is no Linux Redirection support for iso or img files.
But when I checked the Redirection sample program available in AMT 9.5 SDK(ntelamt188.8.131.52gold\IntelAMT184.108.40.206Gold\Linux\Intel_AMT\Samples\Redirection\RedirectionSample), it shows like iso/img can be redirected. README have following details