In consumer photography, image appeal may be defined by the interest that a picture generates when viewed by third-party observers. In this paper, the results of a ground truth experiment on human estimation of image appeal are reported, where 11 participants were asked to rank pictures in 30 groups, based on their relative appeal within their group and comment on the factors that influenced their decisions. Based on their responses, a list of both positive and negative influences was compiled and influences were grouped in general categories that include people, composition, subject, and objective metrics. The results of our experiment indicate that image appeal is related to image quality only with respect to the influences in the category of objective metrics, while the majority of influences belong to the categories of people, composition, and subject. The influences in these categories are scene dependent and fundamentally different in nature from traditional image quality metrics. Thus, when evaluating image appeal a new set of metrics needs to be developed. Individual influences and their relative merits are discussed.