  Photonic SUSY two-loop corrections to the muon magnetic moment are
contributions from diagrams where an additional photon loop is attached to a
SUSY one-loop diagram. These photonic corrections are evaluated exactly,
extending a leading-log calculation by Degrassi and Giudice. Compact analytical
expressions are provided and the numerical behaviour is discussed. The photonic
corrections reduce the SUSY one-loop result by 7...9%. The new terms are
typically around ten times smaller than the leading logarithms, but they can be
larger and have either sign in cases with large SUSY mass splittings. We also
provide details on renormalization and regularization and on how to incorporate
the photonic corrections into a full SUSY two-loop calculation.
