When you click on reply to post look at the 3 rows of images. In the middle row you will find one that is square. Click on it and follow request from computer or URL, depending on which one you are inserting image from click on it and if from a URL copy the location into the box provided, if from your computer click on it and browse your pictures, click on the correct one you want to post then click on upload. When it uploads click on summit. There is a size limit so if it tells you that the file is too large you'll need to resize it to a smaller version.