Change feature image for mobile screens

@ericfrazier

Changing the featured image size for the mobile devices only, requires too much code customization work, which might need to be done via the child theme. Here, this link: https://www.wpexplorer.com/different-images-mobile-users-wordpress/ might help you in this condition.
But, if you want to remove it completely from the mobile devices, then, you can paste this CSS code in the Custom CSS Box provided through the Customizer Options and see if it works:

@media screen and (max-width: 420px) {
    .format-standard .featured-image {
        display: none;
    }
}

Thanks.
Bishal Napit

Thanks for your quick reply. I will investigate this link.

Is it possible to write code that for mobile devices would substitute a different image from the media library in place of the featured image, rather than resize it? That would work fine for me.

Thanks again,
Eric

@ericfrazier

If you are asking to change the featured image per post basis for the mobile devices, then, this seems to not be easily achieved in your site because of the many code customization work. But, if you want the same featured image throughout the site for the mobile devices, then, only small tweak on that code will do the trick for you. The above provided link will change the featured image size for that post. Also, for the information, the file which needed to be edited in the child theme is ‘template-parts/content.php’.

Thanks.
Bishal Napit

OK, the link and file information is helpful. I will work on editing the template-parts/content.php in a child theme.

Thanks,
Eric