> Here is the issue I ran into:
> -*.gif* +*.gif*[< 21]
> That should be "no images except images under
> 21KB",
correct.

> When I only run and exclude filter like:
> -*.gif*[< 21]
> It should return "no images under 21KB",
correct
> however it returns no images at all (I only get the
> HTML files.)
No mind reader here. 
Always post the command line used (or log file line two) so we know what you
did, not what you think you did, the site, etc.
Always post what url you are not getting and on what page.