>>14341400That is one element of correcting data yes, astronomers call those "darks". Another aspect is flatfielding, which is essentially when the sensitivity across an image varies. This can happen in the real world if you have dust on your detector. This can be calibrated by taking an image of a white screen or the twilight sky for ground based telescopes, in space it's a bit harder but is possible. These two issues are probably the case of the blocky background in the JWST image, it should be correctable.
The artifacts in the image I posted are not found in normal consumer cameras, it's an effect called persistence. It's where looking at a bright object leaves an after image in successive images. Here you need to build a model based on previous images, to subtract the effect.
