These are high resolution solar X-ray images from the Yohkoh Soft X-Ray Telescope. They are large files (up to several megabyte) in tiff format.
Publication credit: The solar X-ray images are from the Yohkoh mission of ISAS, Japan. The X-ray telescope was prepared by the Lockheed-Martin Solar and Astrophysics Laboratory, the National Astronomical Observatory of Japan, and the University of Tokyo with the support of NASA and ISAS.
UPDATED!
The Changing Sun, 1991--1999:
TIFF,
40 Mbyte;
JPEG,
1.7 Mbyte
Publication credit: The solar X-ray images are from the Yohkoh mission of ISAS, Japan. The X-ray telescope was prepared by the Lockheed-Martin Solar and Astrophysics Laboratory, the National Astronomical Observatory of Japan, and the University of Tokyo with the support of NASA and ISAS.