A navigational tool is provided for selection of images of interest in large series of images. Difference indices are calculated between adjacent images in the series, and the indices are used to generate a navigational tool which can be presented as a graphical representation of differences between the images. A viewer may select specific locations or sets of images for viewing by manipulation of a virtual tool based upon the representation of the difference indices. The technique thus provides a highly efficient and intuitive tool for location of images in a series where particular features of interest or changes may occur, permitting rapid access and viewing of these images.