Ana here, from the Shopify support team. :)
You can definitely add an image with a clickable link anywhere within your store. If you're using the rich text editor on a product description, collection description, page, or blog post, here's how to do this.
First, insert your image:
Then, click on the image to select it, and click the "link" icon:
Fill in the link info in the pop-up:
Click "Insert link". And that's it! Your image is now a clickable link.
Hope this helps! :)