  We evaluate the electronic self-energy Sigma(E) at an Al(111) surface using
the GW space-time method. This self-energy automatically includes the image
potential V_{im} not present in any local-density approximation for exchange
and correlation. We solve the energy-dependent quasiparticle equations to
obtain surface state wavefunctions, and calculate the effective local potential
experienced by electrons in the near-surface region. We find that V_{im} for
unoccupied states is due to correlation (not exchange). The image-plane
position for interacting electrons is considerably closer to the surface than
for the purely electrostatic effects felt by test charges, and, like its
classical counterpart, is drawn inwards by the effects of atomic structure.
