showing different size splash screen in different devices

Hi all,

   i am trying to display a splash screen ie. an image before the application starts.

   Now for 6600, a 176 * 145 image works however for 6230,a 128 * 128 works.

   Could someone suggest me a way by which an image could self adjust depending on the
   device's screen.

   Any kind of suggestions are welcome.

Thanx in advance,
Amulya