Graphics files can only be opened in DeltaV Operate. DeltaV Operate is also the only application you can use to modify the files, delete the files or create new files. This is true when VCAT is enabled or disabled. When you open a file in DeltaV Operate, DeltaV Operate locks the opened file. This prevents multiple people from editing the same file.
When Version Control is enabled, only one user can check out any given file at a time. That user has control of the file until it is checked back in to the Version Control database. At that point, another user can check the file out. However, other users can open the file in read-only mode. This enables other users to see the file, but not change and save the file.
When AutoCheckOut (or AutoCheckIn/Out) is enabled, the files are checked out for you when you open them in DeltaV Operate.
When Manual Checkout is enabled and you open (in DeltaV Operate) a file that is not already checked out, you are prompted to either check out the file or open it as read-only. If you open the file as read-only, you can perform a Save As and create a new file that is a copy of the opened file but with a new name. When you close the file, it is then added to the Version Control database. The original file is left intact with no changes.