Abstract: A stabilizer precursor comprising a certain halo organic compound having a halogen substituent which is a chlorine, bromine or iodine atom in a photothermographic element or composition provides improved post-processing stability. This stabilizer precursor is useful in photothermographic materials, for example, comprising photosensitive silver salt and an oxidation-reduction image-forming combination comprising a heavy metal salt oxidizing agent with a reducing agent. Certain of the halo organic compounds are incubation antifoggants for certain of the photothermographic materials.