Right-click in your web browser and select View Page Source. This should open up a new window filled with code for the web page. Go up to Edit --> Find (or Ctrl+F) and type .jpg (or .gif, .png, etc.) Select everything from http to .jpg and copy. In the case of your image above, it's "http://img21.imageshack.us/my.php?image=redcross.jpg" Open a new tab on your browser and paste what you just copied.
Also, to make the Page Source shorter and easier to navigate, I'd suggest clicking the post number in the top right corner of the post so you only have to dig through one post instead of 20+.
Fingers crossed that works. If you need any other help, I'll see what I can do.