Am using sigma theme. Without making any changes I have noticed that my images are looking scruffy and pixelated see attached On thumnails and main images
They were fine until today. No changes have been made. Cleared server cache.
Image settings are
default sizes
force jpeg selected  tried it off and on.
crop not selected
Force Image aspect not selected
have tried regen but still returns. This AM was on 1 image, now on a lot of them
site is gold-classifieds.com/

Checked server. No error logs Siteground ran check, all Ok
Disabled all plugins  Made no difference

Uploaded without pixels, but  viewed and downloads as pixelated

Never seen anything like that, try to use imagemagick.

Imagemagick is on.
Completely baffled!
Inspect shows 1 error See image
Which file do I  edit on back-end please ?

It could be hook, footer or user rating? Looks like coding mistake