A Phostint reproduction of an X-ray radiograph of a North American bullfrog is printed on a Phostint postcard published by the Detroit Publishing Company, copyright the New York Zoological Society, catalog number 30. The reverse identifies the image as made from an X-ray negative at the New York Aquarium, produced to show the relation of skeleton to body outline. The card is unused and unmailed.

The frog is displayed dorsal view, spread flat with forelimbs raised and hindlimbs extended downward, the full skeletal structure rendered in dark tones against a warm amber body silhouette. The cranial bones, vertebral column, pelvic girdle, and long bones of all four limbs are clearly delineated, with the webbed toes of both hindlimbs and the individual finger bones of the forelimbs visible in detail. A pale rose tint colors the extremities of the limbs, differentiating soft tissue areas from the denser bone structures at center.

The Detroit Publishing Company's Phostint process, a registered color lithographic printing method, was widely used for natural history and scientific subject postcards in the early twentieth century. The New York Aquarium, then operated under the New York Zoological Society at its Battery Park location, produced a series of scientific postcards using X-ray imagery as part of its public education programs during this period.