Self-Portraits

I'm interested in how painters represent themselves in self-portraits.  What expression and pose do they choose?  Do they look at or past the viewer? What colors stand out?  What is in the background?  How do styles change over time?

Here are some examples that are intriguing to me:

Leonardo Da Vinci (1512)

Judith Leyster (1630)

Rembrandt van Rijn (1661)

Eugene Delacroix (1837)

Claude Monet (1884)

VIncent Van Gogh (1889)

Pablo Picasso (1907)