Picture above: An oil painting by famous Chinese artist Liu Yu-yi.
Original paintings from the Cultural revolution period are fascinating.  In the past few years, I have visited many large auctions held in Beijing and Shanghai and got the chance to take a close look at some original masterpieces of the CR period done by famous artists. 
Of course, among the numerous artists who have contributed in making propaganda posters in the 60's-70's, many have remained unknown and even left the art arena.  Apart from published posters, there are even more propaganda artworks done by local revolutionary parties or peasant painters or school art teachers for use in all sorts of political functions like parades, local or provincial art exhibitions or indoor decoration for government offices.  They can be found almost everywhere during the period.  But with the lapse of time, most of them have been destroyed and only very limited are so lucky to be retained. 
I have seen and got the chance to source some valuable artworks but owing to my financial limits, I only managed to bought some artworks of less famous or unknown artists.  Nevertheless, I adore every artwork in my collection because they are all true exhibits of the political history.  Many artworks of famous Chinese artists done in the CR period were sold at more than a million RMB each at big Chinese auctions during the past two years.  One great artwork by Li Ke-ran was sold at 9.8 million RMB last year.  I was there in Beijing when it was auctioned. 
I have let go some nice oil/gouache ones for the sake of of getting money to support my poster collection.  And here are a couple more, probably last batch of original paintings I am willing to offer to other CR relic collectors........
Lastly, please note that all my original paintings have been with me for 10-20 years.  New reproductions only appears in the past couple of years.  So you can rest assured that these are all authentic artworks of the CR period.