This image is a reprojected portion of Galileo's highest resolution view of Loki, one of the major active volcano's on this fascinating moon. It was taken on Galileo's 31st orbit. While it usually appears dark compared with its surroundings, in this version it appears to have bright areas due to the extremely high phase angle. Loki is on the feature seen on the terminator just above the middle.
Here is another version, which utilizes high pass filtering to better show features within the caldera.
Processed Images Copyright Ted Stryk, Raw Data Courtesy NASA/JPL