Moe Loubani

If you’ve ever wanted to draw on an image or add a caption or text to your image then this is the plugin for you. Best of all it allows you to add your caption, save it, display it, then go back and edit it in different layers and objects laid on top of your image.
It extracts the text from the annotations and displays them as selectable and stylable text just below.
You can hold shift as you draw rectangles to make them perfect squares, same with the ellipse tool and circles.

Image Annotator

This is a plugin that uses the HTML5 canvas and FabricJS to allow you to add shapes and text on top of images and display those images.

Chris Roberts

Annie provides comprehensive annotation options, including footnotes and highlighting. If Tippy is installed, footnotes can be displayed inline using tooltips. Also, footnotes are placed at the end of the post. For highlighting, you are able to use default highlighting styles or define your own.

Annie

Provides comprehensive annotation tools for WordPress posts.

Image Annotator vs Annie