  We estimate the long distance (LD) contribution to the magnetic part of the
$s \to d\gamma$ transition using the Vector Meson Dominance approximation
$(V=\rho,\omega,\psi_i)$. We find that this contribution may be significantly
larger than the short distance (SD) contribution to $s \to d\gamma$ and could
possibly saturate the present experimental upper bound on the $\Omega^-\to
\Xi^-\gamma$ decay rate, $\Gamma^{\rm MAX}_{\Omega^-\to \Xi^-\gamma} \simeq
3.7\times10^{-9}$eV. For the decay $B_s \to B^*_d\gamma$, which is driven by $s
\to d\gamma$ as well, we obtain an upper bound on the branching ratio $BR(B_s
\to B_d^*\gamma)<3\times10^{-8}$ from $\Gamma^{\rm MAX}_{\Omega^-\to
\Xi^-\gamma}$. Barring the possibility that the Quantum Chromodynamics
coefficient $a_2(m_s)$ be much smaller than 1, $\Gamma^{\rm MAX}_{\Omega^-\to
\Xi^-\gamma}$ also implies the approximate relation $\frac{2}{3} \sum_i
\frac{g^2_{\psi_i}(0)}{m^2_{\psi_i}} \simeq \frac{1}{2}
\frac{g^2_\rho(0)}{m^2_\rho} + \frac{1}{6}\frac{g^2_\omega(0)}{m^2_\omega}$.
This relation agrees quantitatively with a recent independent estimate of the
l.h.s. by Deshpande et al., confirming that the LD contributions to $b \to
s\gamma$ are small. We find that these amount to an increase of $(4\pm2)\%$ in
the magnitude of the $b \to s \gamma$ transition amplitude, relative to the SD
contribution alone.
