2007 International Painting Competition, Germany
42 US presidents received honorary awards for paintings on a single strand of human hair.

world smallest painting

Jin Yin Hua    The Portraits of 42 American Presidents (2006)
The Chinese artist Jin Yin Hua is famous for his micro paintings. He paints his works on a single human hair and employs a rabbit hair paintbrush for doing so. To be able to see what he is doing, he has to use a microscope.

Rembrandt van Rijn  Self Portrait (1630)

Rembrandt made approximately 100 self-portraits throughout his life, but this 15 x 12.2 cm illustration was the only one that went through so much quests by itself.

https://www.miniatureartist.com/what-is-the-smallest-painting-in-the-world/