官方文档中提到，Pillow的安装可直接使用pip或easyinstall

pip install Pillow

easy_install Pillow

而实际安装过程中报了一个这样的错误

The headers or library files could not be found for zlib,
a required dependency when compiling Pillow from source.

解决方法如下：
在安装Pillow前先执行以下命令（Linux）

sudo apt-get update
sudo apt-get install python3-dev
sudo apt-get install libtiff5-dev libjpeg8-dev zlib1g-dev libfreetype6-dev liblcms2-dev libwebp-dev tcl8.6-dev tk8.6-dev python3-tk
sudo pip install pillow

若Python2也报相同错误，将上述命令中的python3-dev和python3-tk改为python-dev和python-tk即可