Quick note for today. If you copy the WindowsImageBackup folder say from a network share or another computer to your local computer, and you want Windows Server Backup to recognize it so you can perform a restore, place the WindowsImageBackup folder in the root of a local drive.
Now it can be recognized by Windows Server Backup. From the GUI, when you are asked where the backup is stored, you will choose another location even though you have copied it to the local machine.
Then you can choose the drive it is stored on and WSB will recognize the WindowsImageBackup folder in the root of the drive and will give you the choice of choosing from the backups located in that folder.
If you want to use the command line, you could use something like wbadmin get versions -backupTarget:e: -machine:Server1
That command will look for the WindowsImageBackup folder on the E: drive and list all backups in that folder for the computer named Server1. It is important to include the -machine option if the WindowsImageBackup folder contains folders for more than one machine. You can then use the version ID to perform a restore.
Also keep in mind that since you have copied the WindowsImageBackup folder, you only have the most recent backup performed. Remember, all previous versions are stored on the original backup device as shadow copies.