I see what you're talking about with the image in Firefox being too short. However, in IE7, the image is much larger - around 400 px wider.
IE7
image url:
http://www.multiples.com/howtolastlo...14-03kwide.gif
Dimensions: 1403 x 67
Firefox:
Image url:
http://www.multiples.com/howtolastlo...14-03kwide.gif
Width: 1026px
Height: 49px
I think I've probably gone about as far as I can with this. I just have basic html experience. I'm not sure if you are specifying the width on the img tag itself or what it is contained in, such as a table. You should probably set the 100% width on the container rather than the image itself since the image is so large. I don't know why it would display different on Firefox. I'm guessing you are using different img tags for different browsers.
I hope this helps. If not, posting a sample of your code on vBulletin will probably yield a quick response.
Otp