Jesus Washes the Feet of the Apostles
St. Mark's Cathedral, Venice
Jesus uses his white linteum (John 13:4) to dry the foot of St. Peter, identifiable by his square beard and principal position. Peter's gesture may refer to his request, "wash also my hands and my head" (John 13:9).
The forked beard of the next apostle in line probably signifies St. Andrew, and the curly hair on the next one St. Bartholomew. The next three are anybody's guess, and the six apostles in back are barely differentiated at all.
This image in full resolution
More of the Last Supper
More of the apostles as a group
Photographed at St. Mark's by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.