The New York Public library has put online its collection of color military plates. Most are hand colored block prints. The collection of Mexican Uniforms 1826 – 1906 could come in handy as a painting guide for the Texas Rebellion and the US – Mexican War, as well as the Maximilian period.
The New York Public Library’s digital holdings have an amazing collection of color plates of British uniforms from 1066 – 1900. These are great painting guides.
The New York Public Library Systems Digital Library has digitized images of thousands of plates, prints and paintings, including these of the uniforms of Byzantium through 1453.
Kurtis Brown offers a one-page painting guide to Vikings.