Photos blurred when viewed in Photos but become sharp in edit mode

Thanks for the very plausible explanation, léonie. It would seem that Apple have made a conscious decision that speed and storage are more important than instant image quality in preview. If Apple think they are aiming at photographers then this is a big mistake. Most serious amateur photographers usually take a lot of shots of the same thing which they then used to be able to sort quickly in preview before choosing which shot/s to keep and to delete the rest. Now it's a more tedious task. I only hope someone from Apple reads these communities - and reverses the decision! Thanks again! G.

Thanks very much léonie. That's a fix that works but why do I need to do this now compared with, say, a year ago when it wasn't necessary? Do you know what have Apple done to make this software less user-friendly?