For some time, the MILC Collaboration has been studying electromagnetic
effects on light mesons. These calculations use fully dynamical QCD, but only
quenched photons, which suffices to NLO in XPT. That is, the sea quarks are
electrically neutral, while the valence quarks carry charge. For the photons we
use the non-compact formalism. We have new results with lattice spacing as
small as 0.045 fm and a large range of volumes. We consider how well chiral
perturbation theory describes these results and the implications for light
quark massesComment: Comments: 6 pages, 4 figures. Proceedings of the XXVI IUPAP
Conference on Computational Physics (CCP2014), held at Boston Universit