You have to have the picture available on your computer or a device that you can access from the computer. Click on the "UploadImage" tab. Click on Browse.... Locate the picture you want. I just double click the name of the image I have and it appears in the "upload an image space. Then click on the "Upload" button. It should then appear in your response. Don't forget to click the "submit" button.
I wish somebody will answer this because I also want to know where they get it.