This website (
visit link) has two additional photos and informs us:
"The present (final) position of the Stadium is that of Classical times. The embankments did not have stone seats, except for the preserved platform ("exedra") for the judges at the Olympic games ("Hellanodikae") on the south one. On the north embankment still visible is the altar of Demeter Hamyne. The capacity of the Stadium is estimated to 45.000 spectators. The Olympia stadium was surrounded on three sides by grass embankments where spectators stood to watch the games. The only seats, at the southeast of the stadium, were reserved for judges.
The arched tunnel , just outside the Altis to the northeast, leads to the stadium. A monumental entrance ("Krypte") was erected at the west side of it in the late Hellenistic period. The tunnel was reserved for priests and officials and athletes entering the Stadium for the Games.
The Alpheos River long ago washed away the Olympia hippodrome for chariot races."