Pollard, former editor of the Sunday Mirror and Sunday Express, said the suggestion at the time by the newspapers that the image showed how close Charles was to his sons had angered Diana, who was still hurt following their split.
The image, taken during a ski holiday, showed Charles messing around with William and Harry’s friends, Pollard told Yahoo UK’s The Royal Box.
“This is years and years later and by now she was I think certainly separated, maybe divorced, from Prince Charles,” she said.
“There was a lovely picture of him taking William and Harry skiing I think and they were accompanied by two other boys and in this picture I think Prince Charles pretended to strangle one of the boys.
“We wrote a piece saying ‘he obviously knows his sons’ friends well’, which means he obviously spends quite a bit of time with them, otherwise you wouldn’t pretend to strangle a nine... 10... 11-year-old, and I think she wasn’t very pleased with that.”
Pollard said the picture came at a time when Diana was already feeling hurt and saw herself as the closer parent to her sons.
“She was the earth mother to these boys - you know, all those pictures of them at Alton towers and all those pictures of them on holidays, on Necker, all sorts of places.
“And this was at the stage where I think she was still feeling very hurt and aggressive towards (Charles).
“You know, there are stages in life and that happened then.”