Photothermographic elements capable of producing a high density yellow or magenta image upon image-wise exposure and thermal development at a relatively low temperature and for a short period of time are described. The photothermographic elements of the invention comprise coated on a support base at least one light-sensitive emulsion layer comprising (a) a leuco dye reducing reducing agent, (b) a photosensitive silver halide, (c) an organic silver compound capable of being reduced by the leuco dye reducing agent, and (d) a binder; wherein the leuco dye reducing agent thereto comprises a chromogenic yellow or magenta leuco dye compound.The photothermographic elements of the invention may be used to obtain yellow and magenta images of suitable density in single color or multicolor photothermographic articles. At the same time the chromogenic leuco dye is stable enough not to be oxidized by oxygen of the air or by simple heating and to limit the fog formation after development.