A system for displaying a plurality of registered images is disclosed. A first viewport unit (1) displays a representation of a first image dataset (4) in a first viewport (201). A second viewport unit (2) displays a representation of a second image dataset (5) in a second viewport (202). A position indication unit (7) enables a user to indicate a position in the first dataset (4) displayed in the first viewport (201), to obtain a user-indicated position. A corresponding position determining unit (8) determines a position in the second image dataset (5) corresponding to the user-indicated position, to obtain a corresponding position in the second image dataset (5), based on correspondence information (9) mapping positions in the first image dataset (4) to corresponding positions in the second image dataset (5). The second viewport unit (2) displays an indication of the corresponding position in the second viewport (202).