You will need to install a user script manager extension to install this script.
This addon lets you click on a picture to display it in its native size. This is often larger than the image Instagram shows you when you click it. When you click on the enlarged image, it will bring up the native size image. Clicking it again will get you back to the overview.
Right clicking a video post will remove the overlay so you can enable the video controls.
Auto unmute stories
Recently Instagram starts the stories muted. This script unmutes the stories for you. You can override this by hitting the M button. This will last untill page refresh.