You do have plugins/products on your site unless 3.7 comes with a chatbox now. I can't really tell what else you have on there, but I can tell that you have at least that one product. So, again I'd suggest you disable all your plugins and try adding that same image using the same method and see if it shows up correctly. You may want to also try adding it using the the little image button,

, in the editor also and see if it works then.