I am working on a 2d tutorial and was able to test my current tutorial part on a Samsung Galaxy Tab.
The tutorial simply moves the default icon randomly over the screen.
I have tried your code on HTC Desire HD and the frame rate drops down to unusable after added 20th image using Android 2.2 target. When I exported the same code as android version 2.1 then it worked fine and could handle over 200 instances! I suspect that it is to do with creating instances of your GraphicObject class on 2.2, but not quite sure...