Gallery Image Thumbnails Slow/Fail to Load on Mobile

On a desktop (PC/Mac) my gallery's load completely fine and fast (images are 50-100kb on average) but for some reason if I load a gallery page on a mobile device (Android phone, iPad, etc) the galleries thumbnails are either slow to load images or fail and show the image file name.

The images will generally load if I refresh the page but that is a bad user experience. Any thoughts as to what I can do? 

Link to page: https://www.aprilrainsphotography.com/paris-france

Hi AprilRains,

Did you get an answer for this, or figure it out.  I'm having the same problem so would love to know if you got an answer somewhere else?

Thanks