  The electromagnetic properties of the baryon octet are calculated in quenched
QCD on a 20^3 x 40 lattice with a lattice spacing of 0.128 fm using the
fat-link irrelevant clover (FLIC) fermion action. FLIC fermions enable
simulations to be performed efficiently at quark masses as low as 300 MeV. By
combining FLIC fermions with an improved-conserved vector current, we ensure
that discretisation errors occur only at O(a^2) while maintaining current
conservation. Magnetic moments and electric and magnetic radii are extracted
from the electric and magnetic form factors for each individual quark sector.
  From these, the corresponding baryon properties are constructed. Our results
are compared extensively with the predictions of quenched chiral perturbation
theory. We detect substantial curvature and environment sensitivity of the
quark contributions to electric charge radii and magnetic moments in the low
quark mass region. Furthermore, our quenched QCD simulation results are in
accord with the leading non-analytic behaviour of quenched chiral perturbation
theory, suggesting that the sum of higher-order terms makes only a small
contribution to chiral curvature.
