[The information I have regarding this unusual set of pictures is sketchy, at best - so if anyone can provide me with more detail I'd be happy to update the post.]
While visiting in Hua Hin a while back my friend wanted to stop and have breakfast at what he's remembering as the beach hotel known as the Sailom Resort. After finishing our meal we walked around the grounds some, and I saw several framed photos of King Bhumibol Adulyadej on the wall of an open area near the dining room.
I was told these pictures were taken somewhere in the 1970's when he surprised the people on shore by making an unannounced landing on the beach (without his usual entourage) after sailing from Sattahip on the other side of the Gulf of Thailand. He was far younger and more vibrant-looking than he is today, and it was nice to see the looks on the faces of his subjects during this completely unexpected meeting with their much-beloved King.
The quality of the photos is sadly lacking as I couldn't use a flash and was taking pictures of discolored photos behind glass in low light, but I managed to clean them up well enough to make them worth sharing - I hope.