Here's how to illustrate an iMIS Community post; I'm not sure if it's noted elsewhere.
First, create your new post. Scroll to the bottom and click "File attachments", which expands to show a file path entry field and Browse and Attach buttons. Click Browse, find the image you want, and click Attach. After the file is uploaded, under the Description there's a URL string in very small font. Copy the URL, then in the editor toolbar, click the Insert/Edit image icon (next to the Anchor). In the popup, paste in the URL, then tab out of the field; if all is well, you'll see your picture in the preview. Click OK.
