High-temperature hot spots on Io have been imaged at ~50 km spatial resolution by Galileo's CCD imaging system (SSI). Images were acquired during eclipses (Io in Jupiter's shadow) via the SSI clear filter (~0.4--1.0 &mgr;m), detecting emissions from both small intense hot spots and diffuse extended glows associated with Io's atmosphere and plumes. A total of 13 hot spots have been detected over ~70% of Io's surface. Each hot spot falls precisely on a low-albedo feature corresponding to a caldera floor and/or lava flow. The hot-spot temperatures must exceed ~700 K for detection by SSI. Observations at wavelengths longer than those available to SSI require that most of these hot spots actually have significantly higher temperatures (~1000 K or higher) and cover small areas. The high-temperature hot spots probably mark the locations of active silicate volcanism, supporting suggestions that the eruption and near-surface movement of silicate magma drives the heat flow and volcanic activity of Io.¿ 1997 American Geophysical Union