You can add an image into a post, just by referencing the the url.
Go to the image that you want to insert located on whatever external website > Right click > select properties > Right click > copy and past the URL into your post > highlight the url and click "insert image" which is 2nd icon on the 2nd row of buttons in the post editor.....like this:
The manual way to do this is just past in the URL path to the image and use the tags ["img"] and ["/img"] at either end of the image url (don't include the quote marks)
