The details shared here apply to the most recent versions of Turbo, Parallax, Retina, Responsive, Mobilia, and Artisan. To keep your theme up to date, check out this helpful document.
If you want to make your entire Image with Text Overlay image or Slideshow image a clickable link instead of displaying the buttons, you can follow these instructions.
Step 1: From your Shopify Admin, click Online Store > Themes > Customize to open the Theme Editor.
Step 2: From the Theme Editor, under Sections, open the settings for your Image with Text Overlay or Slideshow. If you don't have those sections added, you can do so by clicking "Add section" at the bottom.
Step 3: Insert a link into the Link field and keep the Button Label field empty. If text is added to the Button Label field, the button will turn into the link and the image will no longer link: