pitumbo.com

Not sure why I was getting a blurry transparent GIF in Firefox, since I wasn't attempting to resize it, but for some reason my image was quite blurred. It looked fine in Internet Explorer (that's a switch - usually it's the reverse and Firefox is the browser displaying as I intended! :). Safari and Chrome were fine too. To solve the issue, one can add:

style="image-rendering: -moz-crisp-edges;"

Voila! Problem solved.