She became interested in portrait miniatures while living in Edinburgh in the late 1950s and was encouraged to publish her research as her knowledge on the subject grew.
Foskett's large photographic archive was sent to the Scottish National Portrait Gallery on a long-term loan in 2003 and her miniatures were catalogued in the same year.
[4] In 1965, the Scottish committee of the Arts Council invited her to curate the coinciding Edinburgh International Festival exhibition ‘British Portrait Miniatures’ at Rothesay Terrace.
[2] The next year, she authored the two-volume A Dictionary of British Miniature Painters containing biographical information on more than 4,500 portrait miniaturists.
[2] She was a consultant on the ‘Artists of the Tudor Court’ exhibition at the Victoria and Albert Museum in 1983 and authored an unpublished but completed manuscript on a major period of the portrait miniature.
[2] She went on lecture tours to London and the United States,[3] and built up a large photographic archive as well as conducting international correspondence on a wide scale.
[1][3] Following her death, her photographic archive and much of her art collection was placed on long-term loan at the Scottish National Portrait Gallery, Edinburgh in 2003.