Another resource that I use for free images is The Commons on Flickr.
The key goal of The Commons is to share hidden treasures from the world’s public photography archives.
The following images are a few of the many results on a search on “color” in The Commons. (Click on any image to go to the corresponding image page on Flickr)
Color guard of Negro engineers, Ft. Belvoir, VA circa 1939, image from Library of Congress
Image taken from page 207 of ‘The Great Battles of the British Army. … With coloured illustrations. (New edition.), The British Library
Image taken from page 71 of ‘Love-Knots and Bridal-Bands: poems and rhymes of wooing and wedding, and valentine verses. The British Library
A dragon – The Illuminated Books of the middle ages; an account of the development and progress of the art of illumination … from the IVth to the XVIIth centuries … Illustrated by a series of examples … executed on stone and printed in colours by Owen Jones. The British Library
Image from page 17 of “On colour, and on the necessity for a general diffusion of taste among all classes : with remarks on laying out dressed geometrical gardens, examples of good and bad taste, illustrated by woodcuts and coloured plates in contrast”, Internet Archive Book
