Some of us are updating the blurry pictures from facebook, when they have got better scans. It can happen, that this pictures seems not to be used at the website. But this is only a technical issue I can not solve.
The problem is the cache of some internet browsers, for example Firefox. It hase got the old picture with the same filename in the "cache" and does not recognize, that there is an update.
Please press CTRL F5 to reload all pictures of a website, when you are updating pictures and still see the old one.