It goes without saying that this module has solved my broken images issue on a few sites and that's great but I'm still trying to really undertand why it's happening.

  1. For example on one of my site pages, an image show by using an imagefield works perfectly fine without this module installed but the very same image inserted using the insert module into a body area does not work unless I activate this module. I've read though the many issues surrounding this which seem to have popped up around Drupal 7.20.
  2. Before I found this module, I tired this code:
    $conf['image_allow_insecure_derivatives'] = TRUE;
    ... in my settings.php file but it did not help to resolve the issue but this module which I think does the same thing does solve it. What is the primary difference and why did the code not work but this module does?
  3. Is there something inherintly wrong with my server setup if I have to use this module?

These are the related issues I've been following but it seems every time I re-read them, it just gets more confusing:

#1934498: Allow the image style 'itok' token to be suppressed in image derivative URLs
#1923814: Existing hardcoded images can break after updating from Drupal 7 earlier than 7.20 if image styles have been re-saved
#1109312: Image derivatives (image cache files such as thumbnails or custom styles) are not created when clean URLs are enabled

I realize this is not a typical support request but I am really struggling to understand this all, Thanks.