Just save the picture on your hard disk then using the attach box chose the file using the file navigator. Click add the file. If you do nothing else the image will appear at the bottom of your post. With each image you add you'll get a dropdown box with all their names in and a button next to it saying place inline. Then you can click this to insert each picture at a certain point in your post. That allows for you to give a little bit of text rather than a whole load of images with no description.