Spent some time trying to figure out why the background image on my site’s home page was not being displayed on mobile devices although it was appearing in a desktop browser. There are, of course, endless solutions that may or may not have worked for someone in the past. They suggested tweaking your CSS coding or adjusting the size of the image or some other voodoo. None of these worked for me.
What worked for me was simply ensuring that the image’s colour profile was set to sRGB. Once that was changed everything worked as expected.