Wellcome Collection, London

Thousands of archival images from the science collections at the museum and library, but look for the "Public Domain Mark" under License of the image.
Photographs in this collection that are available are on the following topics:

Female impersonators (410)

Eyeglasses (328)

Gender nonconformity (90)

Malaysia (89)

Hospitals (86)

Ethnology (85)

China (80)

Universitäts-Kinderklinik (Vienna, Austria) (73)

Male nude in art (71)

Fujian Sheng (China) (66)

India (66)

Hong Kong (China) (63)

Saraks (63)

Museums (62)

Pechili Province (China) (61)

Wellcome Historical Medical Museum (60)

Women (60)

Hospitals - Spain (56)

South Africa (54)

Karachi Plague Committee (India : 1897) (52)