Famous Northern Renaissance artist Jan van Eyck had a penchant for hiding small scale self-portraits of himself into his own paintings; very similar to film director Alfred Hitchcock. First, in order to get an idea of what Jan van Eyck looked like and to see how these tiny portraits are determined to be self-portraits, look at the painting by Jan van Eyck entitled Man in a Red Turban, which is generally recognized by art historians as being a self portrait. Then refer to the following paintings: Madonna with Chancellor Nicolas Rolin (a.k.a. Madonna of Autun), Madonna with Canon George van der Paele, and Arnolfini Wedding Portrait. In the painting Madonna with Chancellor Nicolas Rolin a figure can be seen in the back ground with his back turned to us, he is wearing a prominent red turban very similar to the one worn in the presumed self portrait, Man in a Red Turban. The next two are even more clever. In Madonna with Canon George van der Paele van Eyck paints himself as a reflection in the armor of St. George (the figure on the right). If viewed up close it appears that van Eyck has painted himself actually painting the scene with an easel in front of him. In the Arnolfini Wedding Portrait a detail of the beautiful convex mirror in center of the back wall shows that two figures are entering the room and one is wearing a red turban. Verification that this would be a self portrait is given by the flourished inscription above the mirror, which when translated reads,"Jan van Eyck was here".

There may be more examples of self-portraits in other van Eyck paintings, but these are the only ones that I know about.