birdman
Moderator
That sounds as though the partition on which you have your imagebackups directory doesn't have sufficient free space to unzip an image, but you say there is >900MB.... when it hits zero, I get the image manager screen, but now with an additional entry below the image.zip files called imagerestore (no extension)
Something is going wrong with the unzip, though. Do you have debug logs running (if not, enable them and try again) and what do they show?