I don't like how some images look, how can I restore or re-optimize them?

If you notice that some of your images are pixelated/blurry then you can go to Media Library switch to list mode and just look the the image that looks bad:

Then on the right side of the image you'll see these options:

We recommend you to try first of all to re-optimize the image as Glossy, usually this fixes the issue. In the very rare cases when this doesn't happen then you can also try Lossless.