Arduino to change displayed photos on a computer

Hello,

I'm a beginner and I am looking for a way to make the Arduino switch between two photos displayed on a computer display based on input from a motion sensor (switch when there is motion and switch back when there is not), inspired by this eyeball-aware amnesty ad:

http://thefutureofads.com/amnesty-international-uses-eyeball-aware-ad-to-enhance-message

I know that the Arduino would have trouble switching between photos on its own, and that's why I want the pictures to be stored and displayed on an old laptop I have lying around. Since I'm a beginner I'd like to know how much programming skills is required, and if this is at all feasible. Any replies appreciated!

Have a look at using Processing on the PC. You should be able to find some fairly simple examples to do exactly what you want.

Thanks, I'll look into that.

Another approach if you have a Leonardo, is the Leonardo can act as a keyboard and mouse to the computer. I could imagine you could program the Leonardo to send whatever key sequences you need to change the display to another picture. I don't have a Leonardo, just speculating.