EIT 304. Source
Perhaps you've already figured it out, but these are all pictures of the sun. These up-to-date images come to us courtesy of Solar and Heliospheric Observatory (SOHO), one of the current NASA missions to monitor the sun. Each of these pictures was taken by the Extreme ultraviolet Imaging Telescope (EIT) which takes images of the sun at different wavelengths. These pictures were taken at, in order, 171, 195, 284 and 304 Angstrom wavelengths. Normally these pictures appear black and white right out of the telescope, but these images have been colored in, just like all other astronomical pictures. Each of these pictures shows that the sun is not a boring, featureless ball, but is actually riddled with different temperature regions and high energy plasma arcs.
Sun at visible wavelengths.
In sharp contrast to at non-visible wavelengths, the sun at visible wavelengths is actually quite featureless. This just goes to show what more there is to the universe than what our eyes alone can see.