I'm sure one of the commenters noticed that too, but I can't do a text search of the comments.
Getty Images says this:
https://www.gettyimages.dk/detail/news-photo/president-nixon-introduced-his-new-6-month-old-male-irish-news-photo/515102318
Richard Nixon Walking Dog
(Original Caption) Washington, DC: President Nixon introduced his new 6-month old male Irish Setter, King Timahoe, to the press. Nixon paraded his new pet in the Rose Garden while Senator Everett Dirksen (L) and Representative Gerald Ford (R), GOP Congressional leaders, who had been meeting with Nixon at the White House looked on. The Irish setter was a gift from the Nixon staff. Timahoe is a city in the county of Kildare, Ireland, where Nixon's forebears lived.

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Credit: Bettmann / Contributor
Editorial #: 515102318
Collection: Bettmann
Date created: January 28, 1969
Upload date: March 10, 2016
License type: Rights-managed
Release info: Not released. More information
Source: Bettmann
Object name: u1621031-6.jpg
Max file size: 2913 x 4416 px (9.71 x 14.72 in) - 300 dpi - 7 MB
There are no leaves on the trees, so January 28, 1969, sounds just about right. Nixon had been in office for an entire 8 days.
Everett Dirksen died on September 7, 1969, so this must be among the last photographs of him.
Everett Dirksen
{snip}
Death

President Richard Nixon paying his last tributes to Senator Dirksen in 1969.
In August 1969, chest X-rays disclosed an asymptomatic peripherally located mass in the upper lobe of the right lung. Dirksen entered Walter Reed Army Hospital for surgery, which was undertaken on September 2. A right upper lobectomy removed what proved to be lung cancer (adenocarcinoma). Dirksen initially did well, but progressive complications developed into bronchopneumonia. He suffered a cardiopulmonary arrest and died on September 7, 1969, at age 73.
Dirksen lay in state at the United States Capitol rotunda, followed by burial at Glendale Memorial Gardens in Pekin.
{snip}
Update: I wrote Aaron Blake to let him know about the details of the photograph. I suppose he'll hear from lots of people.