Photos on Mac shwing Pixelated

Thanks for the reply! I connect the phone and download/ import form the phone and also through Photo stream. It's bizarre because show blurred on my phone but mainly on the mac. It's an iphone 12 so not old. For example on my phone there is one image say Img 1012 and the next photo which is blurry is the same image number. But on my mac all the last photos I've taken ar pixelated... screen shots are fine and image scans no problem.

Where is the Optimise mac storage'? Thanks heaps :)

Sorry hope this works :)

When I double click on image it is the same...

This is what it looks like... and info bar shown too. Thanks