Image:  Issue #0004473: Expose openCommand() to translation 
Image:  Issue #0004473: Expose openCommand() to translation 

Continuing the work to expose the undo/redo functionality to translation. This commit does so for the Image Wb.  
Ticket: https://tracker.freecadweb.org/view.php?id=4473
Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master