按照步骤如何安装python映像库（PIL）？用于在Ubuntu 14.04上安装PIL的预安装库。
我收到了这个错误：
Downloading/unpacking PIL
Could not find any downloads that satisfy the requirement PIL
Cleaning up...
No distributions at all found for PIL
Storing debug log for failure in /home/chirag/.pip/pip.log
请帮我解决这个问题......提前谢谢