Hahah, this is a wonderful topic, Helm! I heard about them a while ago, but been reading
this interview recently and this part drew my attention:
Using individual blocks of color to form a precise visual statement is a technique that dates back through the ages at least as far as 4th century Macedonia, arguably reaching its apex with the Christian mosaics of the byzantine empire eight centuries later. It is largely due to the impact of the pixel – that most basic unit of an electronic display – that these grid based pictures are enjoying a degree of uniqueness in the here and now.
If they only knew what we do nowadays!
Avatars were also popular:
http://www.galenfrysinger.com/byzantine_mosaics_greece.htm.
I really like this one, it has interesting feeling to it achieved by the yellow to blue hue shift:
but couldn't find a higher res picture. Is it in your album, Helm?
The image doesn't show up, skamo!