Not working properly on retina displays?

Hey! It seems like that on retina displays, the image with 2x resolution is missing. While it works totally fine on desktop, on my smartphone (s10+) the icons look pretty washed out. Any idea?

Example image: https://s1.imagebanana.com/file/200306/AeX77s88.jpg

The page I need help with: [log in to see the link]