You'd need to know how tall the image is. for example,
<style>
#container{ position: relative; }
#over{ position: absolute; top: 0; right: 0; }
#under{ position: absolute; top: 100px; right: 0; }
</style>
<div id="container">
<image id="over" src="somepic.jpg" alt="some pic" height="100" width="300">
<p id="under">Some paragraph</p>
</div>results in something like:
http://www.custom-anything.com/sand/somepic.jpg
keep in mind, however, that absolute positioning changes how the elements are laid out on the page.
Subsequent paragraphs, images, etc., for example, will not automatically "float" around them; you might end up with over/underlapping content instead.
http://www.custom-anything.com/sand/somepic2.jpg
This is what it's supposed to do, but might not be what you expect.