Exit fullscreen by clicking on image

In the proofing gallery software that I currently use you click a thumbnail to enter fullscreen and then click anywhere on the fullscreen image to go back to the grid view.
In picflow the user needs to move the mouse all the way up to the top left of the screen to return to the grid. For this reason alone I can't use picflow as my daily driver yet.
Getting in and out of fullscreen mode should be as frictionless as possible.