No one has ever produced a copy of the "Thunderbird" photograph, though numerous people, Ivan T. Sanderson being one of the better known, have made claims to its existence.
Jerome Clark speculates that the description of the basic image in question (men standing alongside a winged creature nailed to a barn), is evocative enough to implant a sort of false memory, leading some people to vaguely "remember" seeing the photo at some distant, imprecise time [REF].