Note to Flickr users. Use the embed, copy the link, paste on the page, find the part that starts with "https://live.staticflickr.com" and ends with ".jpg" and copy/cut that, paste that on a blank line and add [ IMG] before the https and [ /IMG] after the .jpg NOTE: remove space after left bracket [. I had to add it to keep it from going into image mode.
Example
<a data-flickr-embed="true" href="https://www.flickr.com/photos/123456777@N02" title=""><img src="https://live.staticflickr.com/61111/5234567890_7234a234sa_h.jpg" width="1600" height="1200" alt=""></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
https://live.staticflickr.com/61111/5234567890_7234a234sa_h.jpg
[ IMG]https://live.staticflickr.com/61111/5234567890_7234a234sa_h.jpg
[ IMG]https://live.staticflickr.com/61111/5234567890_7234a234sa_h.jpg[ /IMG]
Now the image should appear when you preview