Otóż mam pewien problem. Przerobiłem kod ładujący obrazy z resources na assets ( http://developer.android.com/[...]ying-bitmaps/load-bitmap.html ). .jpg ładuje poprawnie a .png nie chce załadować.

private Bitmap decodeSampledFromAssets(String path, int reqWidth, int reqHeight) {

        InputStream ims = null;

        try {

            ims = mContext.getAssets().open(path);

            final BitmapFactory.Options options = new BitmapFactory.Options();

            // 1
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(ims, null, options);
            options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
            options.inJustDecodeBounds = false;

            return BitmapFactory.decodeStream(ims, null, options);
        }
        catch (IOException e) {

            e.printStackTrace();
        }
        finally {

            if (ims != null) {
                try {
                    ims.close();
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        return null;
    }

protected int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        // Raw height and width of image
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {

            final int halfHeight = height / 2;
            final int halfWidth = width / 2;

            // Calculate the largest inSampleSize value that is a power of 2 and keeps both
            // height and width larger than the requested height and width.
            while ((halfHeight / inSampleSize) > reqHeight
                    && (halfWidth / inSampleSize) > reqWidth) {
                inSampleSize *= 2;
            }
        }

        return inSampleSize;
    }

// przykładowe wywołanie

public void test(){
// ładuje
Bitmap bitmap = decodeSampledFromAssets("test1.jpg", 64, 64);
// nie ładuje
Bitmap bitmap = decodeSampledFromAssets("test2.png", 64, 64);
}