[XML-SIG] Ebbeding image data in XML

[Werner F. Bruhin]

I would like to embed an image in an XML file.

I was thinking of using PIL.tostring() and put it into the imageasstring 
element.

<imagedata>
    <imagemode>RGB</imagemode>
    <imagesize>(540, 982)</imagesize>
    <imageasstring>HERE GOES IMAGE DATA</imageasstring>
</imagedata>

Currently I use lxml.etree and get encoding errors when I write the 
image into the element.

I would like the file to XML Schema complient, so what "xs:" type should 
one use for the imageasstring element?

Any hints as always much appreciated.
Werner