Thomas earned a BA from the University of San Francisco in 1960.
Thomas served as Visual Arts Curator for the Contemporary Arts Center in New Orleans from 1988-1995, and as Executive Director of the Houston Center for Photography, Houston, Texas, from 1985-87. The photographer won an Artists Fellowship and a publications grant from the NEA in 1979 as well as an NEA Photographer's Fellowship in 1980 and 1975. He received a publications grant from the San Francisco Museum of Modern Art in 1976.
Thomas explores photography “as a system of information and reproduction," creating photographs, installations, collaborative projects and publications. Since 1971 he has combined “the practice of photography with ideas derived from language and philosophy."
Thomas belongs to the Artists Committee of the San Francisco Art Institute.