I googled for a whole day and didn’t found a solution. I tried a lot of plug ins and so on, but didn’t get it.

If I upload for example that image here: https://deermylove.com/wp-content/uploads/question/20190707_shooting_kinka_beach_0350.jpg

wordpress is generating thumbnails which is ok, but the thumbnails are sooooo unsharp, that I can’t accept it. I also tried 100% JPG quality in the functions.php but it doesn’t solved the problem. I think it’s a resize problem. I think it’s a bad resize algorithm, but I don’t know how to fix that.

After resizing (unsharp, you can see it best in my face):
https://deermylove.com/wp-content/uploads/question/20190707_shooting_kinka_beach_0350-403×403.jpg

Any ideas?

regards
Denis