  The cross section for formation in $\gamma + p$ collisions of the recently
found hidden-charm pentaquark states $P_c(4380)$ and $P_c(4450)$ is discussed
and estimated. The studies of these resonances in photon beam experiments can
be complementary to those in the LHCb experiment setting, and may be more
advantageous for measurement of their additional decay channels. It is pointed
out that both the relative importance of such decays and the yield of the
resonances in the $\gamma + p$ collisions are sensitive to the internal
dynamics of the pentaquarks and can resolve between theoretical models.
Specific numerical estimates are discussed within a simple `baryocharmonium'
model, where the the observed $P_c$ resonances are composites of $J/\psi$ and
excited nucleon states with the quantum numbers of $N(1440)$ and $N(1520)$.
