How to preserve aspect ratio when scaling image using one (CSS) dimension in IE6?

Question

Here\'s the problem. I have an image:

Note no height or width specified.

On certa

Answer 1

Adam Luter gave me the idea for this, but it actually turned out to be really simple:

img {
  width:  75px;
  height: auto;
}

IE6 now scales the image fine and this seems to be what all the other browsers use by default.

Thanks for both the answers though!