Force image to show on calendar on mobile

Site URL: https://grape-smilodon-bk8h.squarespace.com/booking

I am using squarespace calendar and would like to be able to show colours for different prices for different weeks for a rental home.

using simple colour image to display colours, works on desktop and tablet.

On mobile though, the image does not appear so it reverts to shades of grey.

Can I force the image to appear so it colours the blocks, size doesn’t matter as no detail, just colour?

I'd also love this to show on mobile. 

@Barsark found this other thread with some more activity: