My Android app (a text-based games) uses background images a lot in order to provide a better visual ambience. For example, if the action in the game takes you into a tavern, then you get a background image of a tavern in the game. This is a vast improvement, graphically, over the boring black background that you would otherwise get.
It is also a problem, however, since android:background always stretches to the dimensions of the screen. The result is that the background images look very bad if the player swithces between portrait and landscape mode. And to make matters worse, many devices have very different aspect rations (e.g., 320x480 mdpi, 480x800 hdpi, and 480x852 hdpi) and even more variations are coming.
How do others solve this problem? Having individual images for the main resolutions/orientations is not an option for me, as this would result in the apk growing too large.