The man sitting in the chair looking at some papers is Jim's friend Buddy Killen (my friend also), who at that point was employed by Tree Publishing, and is one of the first people Jim met when he came to Nashville in 1955.
Buddy began working at Tree in 1954 at a salary of only $35 but eventually purchased the company and sold it to Sony in 1989 for $40 million! Buddy also bailed Mary Reeves out of legal hot water when she was accused of fraudulently diverting an agricultural loan to another project, and almost went to jail. She needed to raise quick cash, so Buddy told me that without even seeing a list of all the songs in Jim's song publishing companies (Open Road, Acclaim, Tuckahoe), he bought them for tens of thousands of dollars and thus gave Mary cash to settle her legal woes. But in so doing it spelled the end for Mary.
As for the studio pictures, the one of Jim talking to Chet was definitely used for publicity purposes as it has appeared in country music magazines of the time.
The absence of any other musicians in the studio suggests this may have been a staged photo op; however, with Buddy sitting there, it's possible Jim was just doing some quick demos of some Tree songs. Early in his career he did indeed cut some demos at RCA though later used other studios, when "Studio B" became so busy.
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