Is this just pictures you downloaded or other screens too? Hook up an external monitor and see if that makes a difference. With the 'grainy pictures', has this been since the first day you purchased the computer, or is this a recent happening? On almost all laptops, the video card is integrated into the system board. The GPU, Graphics Processing Unit, may have it's own fan on the system board. If the video card is bad then the system board needs to be replaced.