Fig 1 and its legend appear incorrectly in the published article. Please see the correct Fig 1 and its legend here. (Figure Presented). The URL reference in the penultimate sentence of the Materials and Methods section under the heading "Collection of Digital Photographs" is incorrect. The correct sentence is: A complete dataset of all original and filtered images is available at the Harvard Dataverse, URL: http://dx.doi.org/10.7910/DVN/OHWWNR.