My grandma just made the switch from Windows XP to Mac, and she has some eyesight problems and can only read text when it is white-on-black. I have turned on the system preferences option, but this is also inverting the UI and any photos she may be looking at. Apparently, this option in Windows does not invert images and video. I tried to teach her the key combination to switch back and forth to no avail. Does anyone know of an application that will selectively invert the screen, allowing images to be in true color, but virtually everything else be inverted?