I'm working on a website, which features a high-resolution background image. The background image is set with the following CSS
background: url(https://s3.amazonaws.com/ooomf-com-files/XIBPemROQ9iJdUMOOBmG_IMG_1863.jpg) no-repeat 50% 50% fixed;
Wow, it seems Mobile Safari does not support
background-attachment: fixed (or, at least doesn't support it well...)
If you remove that,
background-size: cover behaves as you expect, but it breaks the expected behavior...
There are some work arounds for Mobile Safari involving fixed-positioned elements behind the content to mimic
background-attachment: fixed, if desired.
Off topic, but love the design!