Dear Koders,
I have just added a new theme component which now allows you to annotate your images within the topic compose! 
Just upload your image, and click it on the preview; a new toolbar will appear:
You can add rectangles, highlight or insert text…
Just click the 
to save your changes! Your new image will be published
Regards,
Kodular Team
P.S.: This theme component is (alpha) Image Annotator - Annotate images right inside the previewer! - theme-component - Discourse Meta
It is powered by GitHub - ailon/markerjs: [Deprecated - use markerjs2]: Let your users annotate and mark images