水题：python逆序输出文件

遇到一个奇怪的题目，一个图片文件二进制逆序了。
将顺序转正回来，是个二维码图片。

#!/usr/bin/python

with open("reverse","rb") as f:
    tmp = f.read()

with open("newreverse","wb") as f:
    f.write(tmp[::-1])