On January 4, 2000, near its orbit periapsis, Galileo captured its highest-resolution images of three of Jupiter's four inner regular moons: Thebe, Amalthea, and Metis, imaged from 192,700; 237,700; and 292,600 kilometers away, respectively. The images have been enlarged from their original resolution to a common scale for comparison, and rotated to place north approximately up. Thebe is about 84 kilometers pole-to-pole; Amalthea, 128 kilometers; and Metis, 38 kilometers.
Here is the original data for the above images, with the addition of Galileo's best image of Adrastea.