Adding an image to a forum post

How do I add an image to a forum post?

To upload an image, use the icon circled below, which appears in the top bar of the editor window:


You will then see this:

You may either drag/drop images into the upload window, or click the "Add files" link in the lower left corner.  Once you have selected the images you wish to upload, you must remember to click the "Start Upload" link and wait until all files have finished uploading before you click "OK".