Pat David (Figure A-1) is a talented photographer as well as a free and open source software advocate. He can do incredible things with photographic images using the GNU Image Manipulation Program(or GIMP), G’MIC (a plug-in utility containing of a wide variety of filter effects for GIMP), and other open source photography software.
Figure A-1. Pat David creates incredible photographic images using open source software. (Used with permission © Patrick David 2015)
Mr. David is very active in his advocacy ...