  A method for computing electromagnetic properties of hadrons in lattice QCD
is described and preliminary numerical results are presented. The
electromagnetic field is introduced dynamically, using a noncompact
formulation. Employing enhanced electric charges, the dependence of the
pseudoscalar meson mass on the (anti)quark charges and masses can be accurately
calculated. At $\beta=5.7$ with Wilson action, the $\pi^+-\pi^0$ splitting is
found to be $4.9(3)$ MeV. Using the measured $K^0-K^+$ splitting, we also find
$m_u/m_d = .512(6)$. Systematic errors are discussed.
