Just received this photo and made a high quality scan. It’s a UPI photo from 1967. The original caption states: “Frisco’s Hippies | For three hours, 2,000 ‘hippies’ had a wild time in Golden Gate Park recently. Folk and rock and roll music was played, poetry and speeches were read in the gathering referred to as a ‘Wail.’ There was wild attire, loud music and no real trouble. Credit (UPI Photo) 2/4/67”
Even though the photo doesn’t mention the Diggers, nor the Hells Angels, nor the exact date of the event, there are several internal clues that lead me to think this was taken at the New Year’s Wail event that the Hells Angels threw in gratitude to the Diggers (for raising bail money for Hairy Henry and Chocolate George at the Death of Money Parade the previous month.) Internal clues: this is obviously not Golden Gate Park, it’s the Panhandle. Also: the term “wail” was a Digger term first used at the New Year’s Wail. There is no evidence the term “wail” was used between the date of that first “Wail” (Jan. 1, 1967) and the date on the caption (Feb 4, 1967). So my conclusion is this is a photo of the event where Chester Anderson was inspired to start The Communication Company. (He always told me that seeing the Hells Angels and Diggers together blew his mind. See Chester’s letter to his archivist written soon after this event.)
One item of interest. Look at the attire of the participants. This is months before the “Summer of Love” and most of the onlookers appear to be wearing typical 1960s college attire. Compare this photo to ones several months later in the Panhandle. The man in “wild attire” with umbrella could be considered a cultural virus in this timeline of change.
digger feed: dinosaurs are dancing 
Here’s the Digger chronology listing for the event:
Event: “New Year’s Wail” held in Panhandle. Sunday, January 01, 1967.
Short Note: A New Year’s Day event sponsored by the Hells Angels and the Diggers. The Angels were grateful for the support shown to Chocolate George and Hairy Henry after their arrests at the Diggers’ Death of Money parade.
Long Note: In the Chronicle article, Buddha made a comment on “the joyous moment.” Paul Krassner made a short speech. The Chamber Orkustra performed. The gathering in the Panhandle enjoyed sunny weather on New Year’s Day. The Rec and Park Department ordered the loud speakers turned off but Buddha announced the music would continue from just the amplifiers. “And on until it was dark they played their music and danced and rode their motorcycles and wore their strange clothes and tossed their long hair. And then they packed their guitars and drums and blankets and bottles of wine and rode off into 1967.”
Reference/Source: “Angels Join the Hippies for a Party,” by David Swanston, Chron, 1/2/67, p. 1. See Ringolevio, p. 263. See also Gleason’s announcement two days before the event, Chron, 12/30/66, p. 29.
Judy looked at this photo and suggested that Umbrella Man might have been Pigpen (Ron McKernan), founding member of the Grateful Dead. There’s a resemblance but it’s not certain. The Dead were definitely at the New Year’s Day Wail. Here’s a selection from Ringolevio, page 263:
“The Frisco Angels wanted to repay the people of the Haight for having come through with their brothers’ bail. The club wanted to throw a party and Angel Pete talked about it with Emmett. They decided to have one in the Panhandle on New Year’s Day and they did. It was called the New Year’s Day Wail! and the Angels bought beer, which they gave away to everyone, and paid for the PA system. Emmett arranged for an eighteen-foot, flatbed truck to be used as a stage. Since it was early Sunday afternoon, Emmett had to go wake up Big Brother and the Holding Company, as well as the Grateful Dead. Pearl cursed his being to infinite damnation, and Jerry Garcia suggested he go play Russian roulette with a loaded automatic, but they came and he played his beautiful guitar licks and she sang her trashy soul out for the people.
“It was a great day and a hell of a party–the first free rock-concertparty in any city park put on solely by the people for themselves. By late afternoon everybody was high and happy. The cops came, saw the way everyone looked wasted, and split, muttering something about the absence of a park permit. The crowd shouted a goodbye after them: ‘The parks belong to the people! The parks belong to the people!’ Even so, Emmett believed the cops would have vamped, if the music had continued past dark. But the bands had to gig at the Fillmore and Avalon ballrooms that night, so there was no music. None that was played over the loudspeaker system, anyway. The ‘Wail!’ ended with the falling sun and the Angels rode off on their scooters and everyone else drifted away, smiling with the feeling of having had a good time.”
Aug 28th 1967 was the “Wail” for Hells Angel Chocolate George, my Dad. The first free concert in GG Park. Big Brother and The Dead played. There was a handbill announcing the event calling it his “Wail”