The only information about the picture known can be gathered from the item's description on the auction page:
Uncommon early 10 x 8 glossy news photo of a young Diana lying in bed, with a young man seated behind her, and a bottle of Johnnie Walker sitting on the window sill. Stamped February 1981 on back, the image is clear. The image has crop lines and 'Not to be published' handwritten on the front. Note on back, otherwise light wear. A super early image quite possibly never seen by the public. RR Auction COA.
This raises a few questions: Why, exactly, was this print deemed not worthy of publishing? Is it an old print meant for a school yearbook that didn't make the cut? Or did the Royal Family come across this semi-scandalous portrait and put a stop to its publishing? Was it the bottle of Johnnie? The guy who wasn't Prince Charles? His "SKI BOB" sweater? See the full version below: