[Gimp-user] (seemingly an odd question) getting this image into my email signature?

[FortKnox <forums gimpusers com>]

So I have an odd issue.  What I am trying to do is to add the logo of the gym that turned my life around to 
my Gmail signature, and make the logo a link to their site.  I'm fairly experienced with digital graphic art 
concepts, I've been a GIMP'er for years, yet this one has me stumped.  So if you go to 
http://www.accelerationsport.com/ you'll see their logo in between "Home" and "Weekly schedule."  It's a 
black image with white lettering and a white stick figure.  This one, although this displays as entirely 
white: http://www.accelerationsport.com/wp-content/uploads/2011/02/ASI_Logo-Reverse-White2-2.png  Yet when I 
right-click on it and choose Copy image, then go to my Gmail settings and paste it into my signature, nothing 
shows up.  "Uh?"  So I opened GIMP and chose to Paste from clipboard.  "Oh, now it shows up!"  So I chose 
Select all, hit copy, and tried again to paste it into my Gmail signature.  Yet again, nothing.  So on a 
whim, I inverted the colors, copied, and tried
  to paste again.  Still nothing.

I feel like I'm missing something basic here... would anybody please help me discern what that is?  Why would 
this image appear on the webpage as black but be entirely white in GIMP?  Why is it entirely white when I 
choose View image in a new tab?  What is going on here?

Thanks much,
Jeff

-- 
FortKnox (via gimpusers.com)