So I have a few downloaded photo albums here, about 500pictures which i do not want to import into iPhoto. I already discovered that when i select all pictures i'd like to see and press alt+spacebar a slideshow n fullscreen mode starts. But some pictures are not in the same high resolution as the one my MBA supports. Can i somehow force the OS to automatically zoom into the pictures until my entire screen is filled? I don't want to manually zoom into every picture with a lower resolution.