Photos not loading on SOME mobile phones for homepage + thumbnail images

[KH14]

I have had a few customer's reach out to let me know that the photographs on my website are not loading on mobile. This specifically happens on the homepage and for thumbnails of the products. If you click the product, the page loads with the images (??). I don't know where to start to troubleshoot this because it works and doesn't work for many different types of phones. All images are the correct size and format. I am using the 'Cascade' website theme. Please help!

[beauxbreaux]

What is your website URL?

[KH14]

www.villaobject.com