How to make an image on presentation page responsive?

I need to place a banner in the first text area on the presentation page. It’s fine on desktop and when I place the banner on other pages it’s responsive, but on the presentation page it’s NOT responsive and looks bad on mobile. Is there any way to make an image responsive on the presentation page? I tried a solution I found in another Cryout forum (set the width, then set the height to “auto”) but that didn’t make any difference at all. I often have to put banners on that page, so this is an ongoing problem. Any help greatly appreciated!

Thanks!

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