Wendell, it has been explained a few times. The most important, and most overlooked, step is the picture has to be online somewhere. On an LSC album, or freight shead, on flicker, somewhere online.
When you have the picture on screen, online, you right click the picture, select properties, then highlight the URL. That is the thing that starts with http and ends with .jpg. Then select copy.
Then, here in the thread, in the reply box, there is an icon that looks like a tree with a blue background. click that, and paste the URL into the box next to “Image URL” inb the pop up dialog box. Then click the insert button at the bottom left of that pop up dialog box, and your picture is inserted into the reply box.
Clear as mud?