  We study the implications of the recently improved upper limits on the
branching ratios for the decays B -> rho gamma, expressed as R(rho gamma/K^*
gamma) = BR(B -> rho gamma)/BR(B -> K^* gamma) <0.047. We work out the
constraints that the current bound on R(rho gamma/K^* gamma) implies on the
parameters of the quark mixing matrix in the standard model (SM). Using the
present profile of the unitarity triangle, we predict this ratio to be R(rho
gamma/K^* gamma) = 0.023 +/- 0.012. We also work out the correlations involving
R(rho gamma/K^* gamma), the isospin-violating ratio Delta (rho gamma), and the
direct CP-violating asymmetry A_CP (rho gamma) in B -> rho gamma decays in the
SM, in the minimal supersymmetric extension of the SM (MSSM), and in an
extension of the MSSM involving an additional flavor-changing structure in b ->
d transitions.
