BlackBerry - background image for all screen dimensions

My background bitmap size is 360 X 480. It fits properly for the 9630 simulator, but it does not fit for the 9550 and 8520 simulators. I need to place the image as the background and have it look right on all simulators.

What image size do I need to adjust for all simulators?

I am using the following code to display the background image:

private VerticalFieldManager _manager;
Bitmap backgroundBitmap1 
    = Bitmap.getBitmapResource("initloadsolution.jpg");
Bitmap background_smartBitmap 
    = Bitmap.getBitmapResource("initloadsolution_smart.jpg");   
Background bg1 
    = Back开发者_StackOverflow社区groundFactory.createBitmapBackground(backgroundBitmap1);
_manager.setBackground(bg1);

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Wikipedia says:

480 × 360 pixels (Curve 89xx/Tour 9630/Bold 9650/Bold 97xx)
360 × 480 pixels (Storm 95xx/Torch 98xx )
480 × 320 pixels (Bold 90xx)
360 × 400 pixels (Pearl 3G)
320 × 240 pixels (83xx/85xx/87xx/88xx/Curve 3G)
240 × 260 pixels (71xx/81xx Series)
240 × 160 pixels (72xx/73xx Series)

Also you could resize or crop image on runtime

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you can use blackberry image loader for all type of blackberry device

here is the link

http://www.collegemobile.com/2012/08/blackberry-image-loader/