It takes the sizing values from the <img> tag.
Specifically width and height. If you have only width or only height, it will resize the width or height to the value you specify and the other attribute will be resized in proportion.
It also allows for a size attribute..
<img src=’myphoto.jpg’ size=’70%’>
And this would create a new image that is 70% of the size of the original. And links the new image into url code automatically.