How to add more frames in PowerOff.apk?

Hello,

how can I add more pictures/frames in the PowerOff.apk animation? In my case, there are originally 10 images in the 'drawable' folder - I need to change them (that's no problem) and add 20 more. I realize, that I need to decompile it, but what should I do next so that the animation would work?

Thanks!