Sunspots with their magnetic fields are visible on the right of the photo with their NOAA numbers listed below the image. The spot near the center is larger than the Earth, and the bright area to the upper left of center (labeled 2996 plage) is a gigantic magnetic explosion that hurled high-energy x-rays and particles in our direction. These explosions can produce geomagnetic storms which can cause radio blackouts and can affect satellites. They can produce enough radiation to threaten the safety of astronauts but this one was not that dangerous.
However, SpaceX lost about 40 satellites in February of this year due to a smaller solar flare that induced a geomagnetic storm just as they were being released from the rocket. The storm briefly heated and expanded earth’s outer atmosphere which then degraded the newly released satellites’ orbits and caused them to reenter the atmosphere and burn up instead of ascending to their operational orbits.
Like this flare, the SpaceX damaging flare arose unpredictably from the plage remnants of a sunspot that had faded from view.