Click on Obama's silhouette image to get a free svg file to download. There will be some small pieces, so be careful.
I use Oracal 631 vinyl because it can be removed from the wall without taking the paint off. I also use this type of vinyl for car window and laptop decals. It can get wet, but not constantly, if you have the design on your car window. I've washed my car a few times and my designs are still like new.
Here's some other practice images: