While the Nexus 7 comes with a bunch of stock Jelly Bean wallpapers customizing your tablet to suit your own taste is one of the first things many owners do. It's easy to take pictures that inspire you such as photos of family or friends, landscapes, sci-fi graphics, animals, your favorite movies, tv shows or musicians, celebrities, nature shots etc and use them as a backdrop that'll make your Nexus 7 more personalized. You can also skin icons and buttons and different graphic elements to take the personalization one step further and we'll post a faq on that later.
For graphics and pictures to be used as wallpapers the optimal file size is 1920 x 1408 which allows the screen to be covered edge to edge in both landscape and portrait mode. Many Wallpapers use different sizes however with 1920 x 1280 also being very popular. While the screen resolution of your Nexus 7 Tablet is 1280 x 800 these large resolutions allow for scrolling and the natural up wipe movement of your tablet's screen during normal use while having the background fully or almost fully covered. Other file sizes can be used as well...in fact most are different sizes...but might leave black space around the image if not large enough.
Feel free to post any cool wallpapers you use or have found that you'd like to share with other forum members.