BufferedInputStream in = new BufferedInputStream(
		new FileInputStream(new File(path)));
	BitmapFactory.Options options = new BitmapFactory.Options();
	options.inJustDecodeBounds = false;
	options.inSampleSize = 2;//宽和高变为原来的1/2，即图片压缩为原来的1/4
	Bitmap bitmap = BitmapFactory.decodeStream(in, null, options);