Why are my product images suddenly blurry on mobile?

Website has been working perfectly for a number of years, however today a customer told me that all of the product images are blurry when loading on mobile. What could be the reason for this? It’s literally just impacting the main product images, nothing else. Below is a link with an example.

https://www.mytravelpal.co.uk/products/universal-travel-plug-adaptor-with-resettable-fuse

Thanks. They display perfectly on desktop (and used to display fine on mobile) so I don’t think this is the issue. Further, they show perfectly on the home page preview on mobile, it’s just when you click into the product itself that they go super blurred on the actual product page. Is there anything in the CSS code I should change?

Im trynig to but it says that your number is not on Whatsapp.

I believe the issue is to do with ‘lazy loading’, it’s loading the thumbnail but then not pulling the main images.