I have tried uploading multiple images (All 2000 px and 1 mb size) for my seller profile. On all other places it shows very clear, except at “About the seller” place. I don’t know why? But it is very annoying.
Try a few different sizes.
I saw this problem with my friend. He tried other sizes, wrote in the forum but did not find how to fix this problem. I think this is a general problem and will be solved soon.