Make presplash image fit the screen

I made my presplash image to look good on all my devices with different screen resolutions.
Tested image sizes: 416x530, 256x256, 512x512, 1024x1024.
Tested screen resolutions (both -- portrait and landscape): 320x480, 480x800.

I am not math expert so more testing needed with different image sizes and screen resolutions. May be I just lucky. :)