While you can theoretically make almost any image on your Android tablet into wallpaper for your device, obviously resolution, original quality and aspect ratio is going to affect just how good (or bad) it looks. The following is a quick summary of the best practices for Android Tablet wallpaper, with specific emphasis on devices like the Asus Transformer and the Galaxy Tab running Honeycomb (and hopefully Ice Cream Sandwich when my upgrade is available). Other tablets with different physical dimensions or resolutions may vary.
First a quick diagram to help understand landscape, portrait and rotation of wallpaper. The image below is scaled down from 1920 x 1408 pixels to show how wallpaper actually behaves on the 1280 x 800 pixels of your device.
- Dark Green: This are represents the Home screen of your tablet when it is Landscape mode.
- Light Green: This is the extended area of Landscape mode. It become visible when you swipe left or right to view your additional screens and icons.
- Dark Blue: This are represents the Home screen of your tablet when it is Portrait mode.
- Light Blue: This is the extended area of Portrait mode. It become visible when you swipe left or right to view your additional screens and icons.
- Red: These areas are not shown on the device during Landscape or Portrait mode, however they ARE briefly visible when the devices is rotated and the wallpaper dynamically re-orients itself.
You can download the image above as a Photoshop PSD file. Add your own image on a separate layer and crop, scale or adjust to your liking, then save out as a JPG or PNG.
Transfer your newly created wallpaper to your tablet with your favorite method (I like DropBox), then in the Gallery application, select Menu | Set Picture As | Wallpaper and expand the cropping tool to its maximum size.