Effective photojournalism provokes an emotional reaction and leaves a lasting impression upon the viewer. Striking and memorable images are often said to possess 'impact'. Within cognitive neuroscience memorable emotional images evoke a greater amygdala response. Research to date has focused on arousal as a causative factor, while the contribution of appraisal dimensions relating to salience of an item, goal relevance, or impact are yet to be addressed. We explored how differences in ratings of impact influenced amygdala activity to negative emotional images matched for valence, arousal and other factors. Increased amygdala activation was found to high impact when compared to neutral images, or high impact when compared to low impact images (matched for arousal). Our findings demonstrate that the amygdala response to emotional stimuli is not a function of arousal (or valence) alone and accord more with the proposal that the amygdala responds to the significance or relevance of an event.