I'm testing my application on Samsung Galaxy Ace, and I get the supported sizes with
cameraParams.getSupportedPictureSizes();
It works with all of them except of (320 x 240) - the preview turns black and I get this error: Camera Error 100
Camera Error 100 - "Media server died. In this case, the application must release the Camera object and instantiate a new one."
Do what the SDK says and release the camera object and make a new one.
http://developer.android.com/reference/android/hardware/Camera.html
Read this, too. It might help you: Droid's mediaserver dies on camera.takePicture()