What do you mean?
FOG Doesn’t magically delete files from the system. There is the slight potential of losing [b]AN[/b] image based what we can tell on the size of the file and the length of time it takes to copy the old and the new back over. But it would only delete the image that you are currently working on uploading anyway. FOG does not randomly delete images from your server. The few things I can think of,
First, the /images is not a local disk system on the server but rather a mounted disk that mounts to /images, potentially by a USB connection. Maybe the USB lost access due to standby? This would cause the mount point to no longer exist which would appear as if your images are lost.
Second, the /images is local but there’s a problem with the main drive it’s loaded on? It stops being able to be read, which would give the impression of the drive no longer existing. This would assume you have two hdd’s on the system, one that’s hosting your OS, and one that’s dedicated to your images.