How to Use
Download > Install > Activate. Use your favorite IDE or just edit within the WordPress plugin editor. Change the location on the screen, colour, size, and more.
Example
A fun project plugin but can be used to link an image or the like. About 50% down and 95% to the right on the screen as a 2px X 2px red dot. I also wrapped it in a link to this page. Code includes (commented out) just a dot without link and adding a static image, with a picture of a house fly in the plugin download folder. Looks like there’s a fly on the screen!
Source
This code can be pasted into the functions.php file of your child theme or, download and install the plugin for simple code activation.