Use the browse box on the "My Profile" page to upload an image from your computer. The image has to be 20kb or smaller. The image does not show in the preview so that's why I was doing all the tests. The same image will show in the text box unless you remove it from the Optional Image URL area when you create your post. You can also replace this second image by changing the Optional Image URL with another image as you have done many times before. I hope this is of help to you.
This worked for me, it is a message I got from Paul.