Hi,
Many of those images you are seeing are of the Sun in wavelengths of light (colors) humans can’t see – like ultraviolet and x-rays. We color code them so that we can quickly tell the different “colors” in ultraviolet apart by showing them as different colors of visible light. So, the colors are not real.
See https://stereo.gsfc.nasa....assroom/EUVsun.shtml for more on that and some pictues showing what to look for in solar EUV (extreme ultraviolet) images.

In some cases, like the coronagraph images, the light we are looking at is visible light, but the images are basically black and white – there is no color sensitivity. With those images the color is mostly to help tell apart the images from different telescopes and because it looks nice.

Terry