You can install Pillow with :command:`pip`:

$ pip install Pillow

Or :command:`easy_install` (for installing Python Eggs, as :command:`pip` does not support them):

$ easy_install Pillow

Or download the compressed archive from PyPI, extract it, and inside it run:

$ python setup.py install

Prerequisites are installed on Centos 7 with:

$ sudo yum install libtiff-devel libjpeg-devel libzip-devel freetype-devel \
   lcms2-devel libwebp-devel tcl-devel tk-devel

Solved this way: Uninstalled PIL from virtualenv:

pip uninstall PIL

Installed PIL again using:easy_install http://dist.plone.org/thirdparty/PIL-1.1.7.tar.gz