An image forming process including a heating step is disclosed. The process comprises conducting said heating step in the presence of at least one compound represented by formula (I), (II), or (III). ##STR1## wherein R.sup.1 represents ##STR2## wherein R.sup.11 and R.sup.12 each represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted alkyloxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group or a substituted or unsubstituted amino group; R.sup.11 and R.sup.12 together form a 5-membered or 6-membered ring; Q represents a hydrogen atom or a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted aryl group, or Q represents a group linked to the pyrazole ring, TIME or PUG either directly or through another atom to form a ring; TIME represents a timing group; PUG represents a photographically useful group; and n represents 0 or a positive integer.The image forming process provides for little variation in photographic characteristics even when there is a substantial variation in the heat-processing temperature.