Tweedy-Holmes received a BA in Art History from Barnard College, Columbia University, New York City, in 1964.
A freelance photographer and editor since 1975, she has been coordinating editor for Avon Products, Inc., in New York City since 1978. She served as humanities editor for Columbia University Press (1971-75) and was staff photographer and copy and production editor for Conover- Mast, Inc., in New York City (1967-69). The photographer won Best in Show, first and third prizes in the New York Morgan Horse Society Photo Contest in 1979. Shooting black-and-white and printing without manipulation Tweedy-Holmes makes her subjects the human face and body, animals, architecture, New York City, Paris and still lifes. She uses color for macrophotography of insects. For more than thirty years she has been committed to a self-assigned project-to produce a powerful and extensive group of black-and-white images of captive animals that would compel the viewer to question the concept of wild animals' incarceration as entertainment.
Tweedy-Holmes has belonged to Professional Women Photographers since 1977.