Sorry, I didn't really specify what I meant. The 'Partially Transparent' GIF is a gif with a one of the colours chosen to be transparent, like this:
I make the image transparent with Photoshop and then upload it; I do not make it transparent with CSS. What I am wonding is why it's only see-through when I display it as an <IMG>, but won't when I make the background-Image of a button the same image.
<input style="background-Image: URL(http://www.geocities.com/interpolerater/Button1.gif);">