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.

durgathakur

This plugin allows you to add textual annotations to images by select a region of the image and then attach a textual description, the concept of annotating images with user comments. Integration with JQuery Image Annotation from Chris (http://www.flipbit.co.uk/jquery-image-annotation.html) with PHP support from GitHub (http://github.com/stas/jquery-image-annotate-php-fork).
Some features:
<ul>
<li>Admin page</li>
<li>Option to approve, edit amd remove image notes in admin page.</li>
<li>Auto insert unique id attribute for all the images for image note.</li>
<li>Show notes on other pages such as home and archive.</li>
<li>Gravatar in the notes</li>
<li>Option to sync with wordpress comments.</li>
<li>Option to show thumbnail in comment list.</li>
<li>Option to include post id in every auto insert images id.</li>
<li>‘Mouseover to load notes’ on top of every image note (editable).</li>
<li>‘Link’ on top of every image note if hyperlink image (editable).</li>
</ul>

wp image annotation

Allows you to add textual annotations to images by select a region of the image and then attach a textual description.

Image Annotator vs wp image annotation