This tech-recipe will explain how to use any photo in your stream or any of your Circles photo albums as your Android phone’s wallpaper. This of course only works with Android phones and requires having the Google+ app for Android installed.
1. Launch Google+ on your Android phone or get the app from the Android Market Here)
2. Go to Photos
3. Find the photo in the album you want to use.
4. Tap on the … in the upper right of the screen and choose “Set as Wallpaper”
5. Exit and enjoy your new wallpaper. Quality of wallpaper is dependent on the original size of the upload to Google+.