The method developed earlier to study the stability of small silver panicles (Ref. 7) has becn now applied 10 model the behaviour of latent image specks on silver bromide layers. It has been unambiguously proved that the equilibrium potential of silver specks is determined by the Gibbs-Thomson equation indicating that the potential is always more ncgative than the bulk silver electrode. It is found that the specific surface free energy of the particles is the same on carbon and silver bromide, but is profoundly lowered if the particles on either substrate are covercd with a thin layer of gelatin. Thus the well known stabilizing effect of gelatin on latent image specks can now be explained simply by its strong influence on the specific free energy of the interface. It is further argued that the results justify an extrapolation based on the Gibbs-Thomson equation, allowing thus an approximate evaluation of the critical size of the developable latent image speck. This, in strikingly good agreement with other estimates, is found to contain not more than 10 atoms of silver. The results are believed to support substantially the elcctrode theory of development. Depending on ΔE of the developer, a speck containing a few atoms of silver is already stable on the silver bromide/gelatin interface and it stans to grow by extracting electrons from the reducing agents. The induction period eems to be connected with geometrical restrictions, since electrons can be injected only through the surface of the growing silver peck.