Yes, I am genial.... if you need to ask the question, you clearly haven't bothered to look yourself; and a detailed answer such as this takes time (a lot more time than it would have taken you to look yourself).
The Features page
on this site mentions that images are supported, and even shows a sample spreadsheet with images.
You could also try looking in the Documentation:
The PHPExcel developer documentation file has sections entitled:
Reading Images from a worksheet
Add a GD drawing to a worksheet
or some of the examples in the /Tests directory
04printing.php (example of images in a print heading)