That link is useful if you're going to be displaying the results on a non-HubSpot page. However, it does require a developer who knows how to work with an API.
If you're interested in changing how the search results appear on a HubSpot hosted page, in your Design Manager, you can search for the "Site Search Results" template, clone it and customise it. Again, it does require a developer with HTML and JavaScript knowledge.
Unfortunately in my tests I haven't found a way to pull the page image. The documentation shows no way to pull it and any parameter I've tried (image, featuredImage, summary_large_image...) doesn't seem to work.