Photoshop :: Extracted Image Displays Differently In Browser Than CS5?

[URL]What I want to do is to extract the girl's image and save it with a transparent background as a gif, and then put it up on the web page I've created, which has a dark grey gradient background.

The problem is when I do that, the contour of the girl's image contains a lot of white space and what appears like brush strokes! The white space doesn't show up at all while I'm using the Refine Radius tool on a black background. It also doesn't show up when I save the image as a gif on a dark background layer in Photoshop. It only appears when I save it on a transparent background and display it on my web page!

Here's the image, saved on a dark background:

Here's the image, on a transparent background, displayed on the live web page [URL]