Photothermographic imaging systems based on silver halide and silver carboxylates have been utilized for a wide variety of imaging applications for many years. We have been investigating the morphology of silver particles formed in the image area of photothermographic imaging systems in order to understand the forces that affect their morphology. Because the size, shape, morphology and silver particle distribution within an image area affects the overall optical properties of the imaging material, control of these properties should lead to improved photographic responses of the materials. We have found in this investigation that there are multiple factors that influence the overall morphology of the silver particles, and show how morphological properties are changed by different conditions, e.g., the nature of the materials used, including the toners (succinimide, phthalimide, phthalazine), phenolic developers, and related components.