This study examined the relationship between image vividness and psychophysiological responses to trauma-related stimuli in participants with Posttraumatic Stress Disorder (PTSD). An auditory stimulus related to a shared trauma was presented to participants with and without PTSD and physiological parameters (heart rate and blood pressure) were measured concurrently. A negative correlation was noted in the PTSD group between image vividness and the level of physiological response. When the PTSD group was divided into high and low vividness, the physiological response was higher than that of the non-PTSD controls only when image vividness was low. The results are discussed in the context of Lang's theoretical model, emphasizing the role of image vividness in the mediation and regulation of psychophysiology.