You need to use the full image URL location. You cannot use the "rewrite" path that X3 is using within the application ...
http://www.merelyafleshwound.com/conten ... rse-02.JPG
Even X3 loads your images like this ... You can right-click an image, open in new tab and you will find something like this to a resized image:
http://www.merelyafleshwound.com/render ... rse-02.JPG
Replace the
render/w800-c3:2-q90/ with
content/, and you have the full url:
http://www.merelyafleshwound.com/conten ... rse-02.JPG
Just because X3 generates "nice" page url's, doesn't mean the images are physically located in the same nice url's.