Comment by skew-aberration

I think that still simplifies a bit too much. Wilkins studied DNA structure with several methods from 1948-50 but when his best results were from a modern x-ray diffraction image, Franklin (an expert in the field) was hired to essentially take over the project (which he resented).

The first images that Watson saw were actually taken before Franklin joined the team. Better images (and her analysis of them) were some of the most valuable pieces of evidence for narrowing down the possible structures (e.g. they disproved models by Pauling/Watson/Crick) - but by late 1952 Wilkins felt they had enough data and ought to focus on modelling. Franklin (who certainly had an ego of her own) insisted on continuing with her approach - she was an expert in these techniques after all and was making real progress.

Wilkins (who had been had been open with his own inconclusive results), eventually went over her head and showed the famous images to Watson and Crick. He felt they were sufficient to guide the model building and he was frustrated that Franklin had been withholding them while pursuing the wrong research directions. Franklin mocked him for his views at time, but Wilkins was somewhat vindicated.

I don't think this should be considered ironic, or that the image held all the answers, or that the discovery was stolen. Ultimately her work played exactly the role it was intended to, eliminating candidate models. The subsequent diminishment of that role is the real controversy, and most involved later walked back some of their statements.