python-imaging/Pillow — pull request #11 by larsyencken (2012-09-05 03:27:43+00:00)
Title: Fix a bug in quantize() causing crashes.

From German Bravo's Image-SIG post:
http://mail.python.org/pipermail/image-sig/2012-June/007047.html

"I found a nasty bug in PIL's quantize(), in Quant.c,
map_image_pixels_from_median_box(), the `int pixelVal;` definition
must be `unsigned long pixelVal;` instead... This was making PIL crash
under certain circumstances in my system (64 bit Mac OS X Lion 10.7.4
using llvm-gcc4.2)."

This bug has been causing issues in downstream libraries such as Colorific on OS X. https://github.com/99designs/colorific/issues/3