0 images smushed out of 242

Hello,

I have a lot of images in my media folder and the main reason i’m not ranking high on Page Insights on mobile is due to deferring images offscreen. The recommendation was to use Smush which I did. However after smushing it didnt smush any of the 242 images i have in my media library, how is that possible? Is there something a dev can do to fix this?

I am storing all my images on a different server, Amazon S3 storage to be exact so is there any way Smush can look for the images on Amazon or do they need to be on my actual server connected to my WordPress site?

Kind Regards,
Robert