This is going to sound nit-picky but I invite you to do it say 50 times.... mouse is in the right hand... take your hand off the mouse find the "P" on the keyboard.... press it... reach back to locate the mouse and mouse to the next image... rinse and repeat... you'll see that it's a lot of looking up and down to find a key on the keyboard and the mouse on your desk. Compare that with never looking down to target a key on a keyboard nor taking you hand off the mouse. Do it 200 times and you'll see the time wasted IMHO.