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.
painting guide
English Civil War Unform Guides
Here are a couple of short guides to English Civil War Royalist and Parliamentarian uniforms.
Viking Painting Guide
Kurtis Brown offers a one-page painting guide to Vikings.
Note: the link above is dead, and an email to Kurtis bounced. So I went to the Wayback Machine and retrieved a copy of the page. It is preserved below for posterity.
Photos of 1/72 World War II Model Airplanes
JD Burgess has a site with dozens of outstanding photos of World War II model airplanes. Each model not only has the traditional 3/4 on photo, but also left, right, rear, above rear, above left … well, you get the picture.
These would make a good painting guide for air war miniature wargamers.
Spanish Uniforms Painting Guides
The Uniformes Militares Espa�oles site has extensive color plates of Spanish Uniforms for the years 1800 – 1980.