Fortunately for Seitz's project, a computer program should be able to do more than a reference manual. First, to teach the program to accurately identify weapons, Seitz fed the Imagga tagging tool images of just the guns themselves, no people attached. Then he tried with images of people holding guns. The tool tried to tag other things, like "fashion" instead, but with some manual cropping, it recognized the weapons again. Manually cropping images defeats the point of an automated weapon-identifier, so he coded a python function that, in essence, looks at the image in chunks, tags them, and then only keeps the tagged sections with desired keywords ("gun", "weapon," "glock", etc).