How can I include svg / png / vml images directly

Question

I want to include (if I even can) include directly an svg image into an xls sheet that is written in xml like

<Worksheet><Row><Cell></Cell></Row></Worksheet>

I want to embed them directly but I don't know how I can do this in xml and what works in excel 2003.

Or doesnt it even work with ms excel? I need to show an svg image directly in an excel sheet.