The other trick requires a two step process, but it doesn't break images when you forget and delete something next year. Attach the image using the 'Attachments and other options' below. Then once you've posted your posting with the images as attachments, you can open them up by clicking on them, grab the url, then put it in image tags. They'll be visible twice - once full size and once at reduced size, all at the bottom. But that way you don't have to host them.