I don't know if this is related but on Friday I was unable to see the icons, the pages took ages to load, and only partially. The only site I had trouble with was Pprune, all my usual news, banking (yes, that's a 'b'), and other sites were fine.
I checked my download speed, it was 4mb, which is faster than I have often got in the past, so no problem there, but when I rebooted my router the problem was solved. No idea why!