BUG: Fix libpng warnings in console when loading images with Qt 4.8.7

Created by: msmolens

This commit eliminates the following libpng warning seen when loading certain PNG images using libpng 1.6.x, which is included in Qt 4.8.7:

libpng warning: iCCP: known incorrect sRGB profile

To fix the images I ran them through ImageMagick, which removes the incorrect profiles, as suggested in [1]:

convert image.png image.png

libpng 1.6.17 describes the warning in png.c line 2308:

/* These profiles are known to have bad data that may cause
 * problems if they are used, therefore attempt to
 * discourage their use, skip the 'have_md5' warning below,
 * which is made irrelevant by this error.
 */

[1] http://stackoverflow.com/questions/22745076/libpng-warning-iccp-known-incorrect-srgb-profile