Heyman was born in Danbury, Connecticut, to real estate developer Lazarus Heyman and Annette Heyman. She attended Sarah Lawrence College, graduating in 1964, and embarked on a career as a photographer. Her first photography exhibit was in 1972, and in 1974 she published the book that won her acclaim, Growing Up Female: A Personal Photo-Journal. She soon after published another book, this time focusing on working women: Butcher, Baker, Cabinetmaker (1978).
In the late 1970s Charles Harbutt invited Heyman to join Magnum Photos, one of the first women to be so invited. In 1981, Heyman, along with Harbutt, Mark Godfrey, Mary Ellen Mark, and Joan Liftin, co-founded Archive Pictures Inc., an international documentary photographers' cooperative. In the 1990s, Heyman joined the International Center of Photography in Manhattan as director of the documentary and photojournalism department.
She was married twice, and had one son, Lazar Bloch.