安卓根据需要压缩图片大小bitmap，drawable

public static Bitmap zoomImg(Bitmap bm, int newWidth, int newHeight) {
        //获得图片的宽高
        int width = bm.getWidth();
        int height = bm.getHeight();
        //计算缩放比例
        float scaleWidth = ((float) newWidth) / width;
        float scaleHeight = ((float) newHeight) / height;
        //取得想要缩放的matrix参数
        Matrix matrix = new Matrix();
        matrix.postScale(scaleWidth, scaleHeight);
        //得到新的图片
        return Bitmap.createBitmap(bm, 0, 0, width, height, matrix, true);
    }

Bitmap bitmap = zoomImg(BitmapFactory.decodeResource(getResources(), R.drawable.icon_gcoding), 70, 100);