What is Android HVGA Devices Wallpaper Size?

In first release of Android OS up to ver 1.5 HVGA is the only screen size supported which is 320x480 resolution. But Android phone have a very unique homescreen background that will change when you scroll to left and right,  that will make the wallpaper for Android phone is bigger than in screen resolution. From my observation the homescreen background is change about 160 pixel left and right, so the exact size of Android HVGA wallpapers is 640x480 pixel resolution. If you would like to create your own  wallpaper for Android HVGA devices you need to re-size or crop your image into 640x480 resolution.
Example of Android HVGA devices G1, MyTouch 3G aka HTC Magic, HTC Hero, HTC HD Mini, HTC Legand, many more to come.