  Using modern high-resolution observations of extragalactic compact radio
sources we obtain an estimate of the upper bound on a photon electric charge at
the level $e_{\gamma} \lesssim 3 \cdot 10^{-33}$ of elementary charge (assuming
the photon charge to be energy independent). This is three orders of magnitude
better than the limit obtained with radio pulsar timing. Also we set a limit on
a photon charge in the gamma-ray band (energies about 0.1 MeV). In future the
estimate made for extragalactic sources can be significantly improved.
