In a photothermographic silver halide composition capable of being coated on a support comprising a hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer with an organic solvent mixture, a hydrophobic binder and an oxidation-reduction image-forming composition comprising (i) a silver salt of a long-chain fatty acid with (ii) an organic reducing agent, improvements are provided by a solvent mixture comprising a combination of (A) an alcohol photographic speed-increasing solvent which is a compound selected from the group consisting of benzyl alcohol photographic speed-increasing solvents and 2-phenoxyethanol speed-increasing solvents with (B) an aromatic hydrocarbon solvent that is compatible with the alcohol solvent and (C) 0 to 10% by weight of the solvent mixture of such hydrophobic binder. The described photothermographic composition can be prepared by very thoroughly mixing, such as ultrasonic wave mixing, (I) a hydrophilic photosensitive silver halide emulsion with (II) an organic solvent mixture comprising described (A), (B) and (C), and then very thoroughly mixing the resulting product with (III) comprising (a) a hydrophobic binder and (b) an oxidation-reduction image-forming composition comprising (i) a silver salt of a long-chain fatty acid with (ii) an organic reducing agent, typically in an organic solvent. The photothermographic composition can be coated on a suitable support to provide a photothermographic element.