I'm Martin Walker. I'm originally from Newcastle, England, but now I teach organic chemistry at the State University of New York in Potsdam, New York. I have been taking pictures of chemicals for Wikipedia since 2004, and of chemists since about 2005. I mainly post pictures somewhere in Category:Inorganic compounds or Category:Chemists and I post ChemSketch or IsisDraw schemes in Category:Organic_reactions. I'm someone who instinctively prefers categories to articles in Commons, though I wish category images were searchable like articles.