I read about this somewere, I think it was developer.android on the widget page, they give you some stock images and say add 'noise' to reduce banding.
This is confirmed by this link: http://androidforums.com/htc-evo-4g/115 ... ients.html
Which also links to: http://www.planetphotoshop.com/say-good ... nding.html
Which then links back to my superior skills and your favourite resource DEV.AND ! :http://developer.android.com/guide/prac ... tml#tricks
In some cases, devices have low pixel depths that can cause visual banding and dithering issues. To solve this, application developers should pass assets through a "proxy" drawable defined as XML:. This technique references the original artwork, in this case "background.9.png", and instructs the device to dither it as needed
Keywords: Android, Banding, Images, Tearing, Image, Resolution, Poor, Quality, PNG, Gradiant, Drawable