参考学习博客。
http://blog.csdn.net/icamera0/article/details/50762050
http://blog.csdn.net/column/details/pythonpil.html?&page=2
http://pillow.readthedocs.io/en/latest/reference/Image.html
Python PIL模块
原文：http://www.cnblogs.com/lwsup/p/7260767.html
