Hmmm. Feels like something squirrelly is going on. Suggest breaking things up to make them very step-by-step, to make sure each piece of the puzzle fits. Here's some code that works for me:
mContext = getApplicationContext(); mRes = mContext.getResources(); mBitmap = BitmapFactory.decodeResource(mRes, R.drawable.myimage, mOpts);
(This way you can make sure your resources are good; not sure what else to suggest except converting file to png) Also--your bitmap should be 480x800 not 800x480.