Freda Collier (née Ticehurst) was born at St. Leonards-on-Sea, East Sussex in 1916. She started her photographic career working at the General Electrical Company and it was here she met John Randall.
Randall was one of the team at King’s College London, with Maurice Wilkins and Rosalind Franklin, working on the structure of DNA. Randall invited Collier to work with the team and in 1950 she started working in the laboratory as an x-ray photographer, eventually heading the photographic laboratory there.
It was in this laboratory that the famous “photo 51” was taken in 1952 and it is likely that Collier was the one who took it alongside Raymond Gosling who was working as a PhD student under the supervision of Rosalind Franklin. It was Franklin’s understanding of x-ray diffraction and physical chemistry that allowed such a high quality photo to be taken – previous photographs were not as clear due, in part, to the difficulties of sample preparation.
When James Watson saw the photo it was the inspiration he needed to solve the structure of DNA and it was a key piece of evidence in Watson and Crick’s paper for which neither Franklin, nor Collier, received acknowledgment. Franklin has only recently been recognized for her contribution to the solution to the structure of DNA.
According to her nephew, AP Thirlwell, Collier was a close confidant of Franklin and it was a great regret to her that Franklin’s contribution was not fully recognized at the time. Freda Collier died in 2013 aged 97 survived by four nephews and five nieces.

Further reading
I have not been able to find much information about Freda Collier. The main source is an obituary written in the Guardian by her nephew, AP Thirlwall, in 2013. There is also a letter to the Guardian from the same source.
Thank you to Dr Kersten Hall for telling me about Collier and his fantastic book, The Man in the Monkeynut Coat.
Freda (Ticehurst) was played by Jill Johnson in BBC’s Horizon 1987 documentary “Life story” (IMDB).