The technology described in this document can be embodied in a method of displaying images of portions of a human body on a display device. The method includes receiving a representation of a plurality of images that includes images of at least two different modalities, and location information corresponding to at least a subset of the plurality of images. A first image of a first modality is displayed on the display device in accordance with the corresponding location information. A second image of a second modality is overlaid on the first image in accordance with corresponding location information. At least a third image is overlaid on the first image in accordance with corresponding location information, the third image being of the second modality, and the second and third images being displayed concurrently for at least a period of time.