matplotlib/matplotlib — pull request #623 by stefanv (2011-12-13 01:55:39+00:00)
Title: Do not assume < 8-bit images are 8-bit.

When loading PNGs with bit-depth < 8, matplotlib assumes the bit depth is 8. This causes black and white images to be returned in the range [0, 1/255] instead of [0, 1].

This PR is about indicating where the problem occurs, more than trying to be a complete fix.

A sample image for testing may be found here:

http://mentat.za.net/refer/circles.png