Socialists Don't Believe in Royalties
The cool thing about Chinese propaganda posters is they were almost always painted by an artist listed as "unknown" and they're done for a foreign communist government, so you're free to abuse the often stunning artwork without fear of legal reprisal and those pesky Cease and Desist letters. As noted on the website where I lifted these fine images:
"The designers/artists of the posters were employees of the art academies, museums, or publishers. During the high tide of socialism, it was seen as counterrevolutionary to exercise personal claims to the copyrights over the works. It would be safe to consider the academies, etc., as the copyright holders. Now, in our experience, these institutions do not exercise their copyrights for materials published in the period 1949-mid-1980s. With the Chinese adoption of the ISBN-system, all this has changed, of course."
Some of the original wording on these is great stuff, like "Resolutely cut off the bloody and criminal hand of the American aggressor that spreads germs!" from 1952. Or this gem from 1950: "Family members, relatives and friends of criminal secret agents, you must supervise and urge criminals to register and turn over a new leaf!" And apparently there was a campaign to murder all the sparrows, which they did, only to be plagued by bed bugs.
So until the Chinese are your overlords and they put all of us who work in "the arts" either to death or to work in the propaganda sweatshops*, feel free to use these in your campaigns. (See what some have done here.)
* You think your Creative Director is a dick? Wait'll they're telling you EXACTLY what to design and write.