Take a temporary picture of a region of interest of a VI

I want to be able to take a picture that will be stored in the temporary files, of  region of interest in a VI. The thing is that the region of interest will be located in the far end left side of the VI, so it will not be seen on screen, but I still want to be able to programatically take a picture of this region of the VI.

Can someone please tell me if this can be done and how to do this?

Thanks in advance!