Images are not rendering in Chrome either. Checked the console. This is the error that you are getting. Failed to load resource: the server responded with a status of 403 (). Here is a link that tells you what is means - Error 403 - Mozilla
I’ve noticed the background image, fetched from unsplash, was actually rendering on mobile. Unlike the carousel pictures referencing to my google photos account.
I then solved the problem by hosting the carousel pictures on my GitHub account instead of google photos and now I can see them from my iPhone as well and everything’s working fine