1. Store your image in a location that will generate a URL like Flickr, or Wikimedia Commons and get the File URL
2. In Omeka-S add an HTML block to your page and click inside the HTML box to display the menu options. Open the source code editor [<>] from the menu options.
3. Then, use this code snippet to add the linked image - paste it into the source code editor box. Be sure to replace the bold italic text with your website URL, and the File URL where indicated.
<p> <a draggable="false" href= "enter-your-website-url-between-these quotation marks"><img alt="poster with drop of water" class="middle" draggable="false" height="600" src="enter-your-image-file-URL-between-these-quotation-marks" style="margin:auto" width="100%" /></a></p>
This Omeka page (LINKED IMAGES USING HTML) is an example of how I used the code snippet below
<p> <a draggable="false" href="https://perma.cc/5P4N-JGYZ"><img alt="poster with drop of water" class="middle" draggable="false" height="600" src=" https://upload.wikimedia.org/wikipedia/commons/5/5e/Water_drop_001.jpg" style="margin:auto" width="100%" /></a></p>