Here are some quick CLI commands to get those CD/DVD images mounted under Linux (without having to burn them first).
# ISO
mount -t iso9660 -o loop,user file.iso /path/mount_directory
# MDF
mount imagen.mdf /path/mount_directory -o loop=/dev/loop0
# NRG
mount -o loop,offset=307200 imagen.nrg /path/mount_directory