Hello! We are able to do this, by attaching the image as an attachment. When creating a post (not the quick reply), there is a button on the top toward the right, that has a paperclip on it, shown here:



If you click on it, a box pops up and you can hit browse and search for the image you want to post.





Hit upload, and the box should now look like this:



Click out of box, and your attached file should be under the text box, under Additional Options, as shown:



Your published post will have a thumbnail of your image that you can click on to make it larger. Clicking on the picture again will send you to the direct link to the picture in its original size. The thumbnail for the image I uploaded is below. Try it out.