Learn how to create a thumbnail image.
Read on how to do it in this link: https://www.w3schools.com/howto/howto_css_thumbnail.asp
Thumbnail Image
A thumbnail is a small image that represents a larger image (when clicked on), and is often recognized with a border around it:
Try it yourself here: https://www.w3schools.com/howto/tryit.asp?filename=tryhow_css_thumbnail_image