<a href="https://chineseposters.net/" target="_blank" rel="noreferrer noopener">Chinese Posters Propaganda, Politics, History, Art</a>
This is the most popular archive among my students.
Source of Image:
Xin Liliang - New view in the rural village
https://chineseposters.net/posters/e12-527.php
<a href="http://idp.bl.uk/" target="_blank" rel="noreferrer noopener">The International Dunhuang Project: The Silk Road Online国际敦煌项目</a>