  We present a 2+1--flavor lattice QCD calculation of the electromagnetic Dirac
and Pauli form factors of the octet baryons. The magnetic Sachs form factor is
extrapolated at six fixed values of $Q^2$ to the physical pseudoscalar masses
and infinite volume using a formulation based on heavy baryon chiral
perturbation theory with finite-range regularization. We properly account for
omitted disconnected quark contractions using a partially-quenched effective
field theory formalism. The results compare well with the experimental form
factors of the nucleon and the magnetic moments of the octet baryons.
