I just found this forum, so this is my first posting for which you have obviously touched upon a topic area for which I have in the past, done extensive private research and investigation into.
OK Now to begin..
The photo or sets of photos, some of which you have posted here, allegedly claimed to be from Paul Valli, Neil Slade, etc, are actually taken from a series of photos originating, from a home movie clip taken near Merlin Oregon by Tahahlita B. Wiese Fry, A former wife of UFO contactee Daniel Fry.
Tahahlita B. Weise who's real name is also Bertha Mantzurani, while she was gathering home movie footage to sell her property near Merlin Oregon, took film footage of this suddenly appearing UFO (1964) which was later stolen by her real estate agent, Fritz Van Nest, who later made several attempts himself to profit from the photos.
Fritz Van Nest relocated himself to Kanab Utah 4 years later and claimed to have taken the photo himself by a lake near that location while on a camping trip. In the process, several cropped up photos of this type have been printed in different formates, sold, circulated and yet reclaimed by many individuals adding in their own copyrights to the photos, all within the past 40 years. About 4 or so years ago, I was able to find many of the different copyright holders and bring them all to each others attention, but as one of then would say to me, "Talk about a tempest in a teapot"! On one occasion the photo was even made into an X-files poster.
For those interested, I do have further poof of this story, because I have a portion of the original film clip, reversed mirror imaged, along with a collection of these same photos.
Others who have made claims to the photos since Fritz Van Nest, include...
-Bill McDonald who received the photo submitted to him by a Bruce Smith on 08/09/2003.
-Bruce Smith who took it from Gerry also in 2003.
-Dr Oren Swearingen who received the photo or photos from Bob and Yolanda Curtis.
-Neil Slade who received the photo from Henry Rowland, who then claims was from the brother of a client.
Note: Paul Valli had no association with the photo.
Peace in knowing,