centreing of images using html percentages

I am wondering how i would place an image in the centre of my page using a percentage.

any help would be so much help ta in advance

well a few questions first:

1) is it the only thing on the page?
2) is it to be horizonatally and vertically centered?

depending on those you might not even have to use percentages.

A littl emore info would deffinately get you an answer that will suit your needs better.