[xsl] Image size with XSL?

["Mark Wilson mark@xxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

I have an XSL stylesheet driven by an XML data source that produces 
about 5000 different pages, many with multiple images. I have been 
adding by hand a placement-index to the XML data source that arranges 
the images neatly, as with this page:
    http://www.cpslib.org/amp/europa-themes.htm.

I am now faced with adding a huge number of images to a page or pages 
like this:
    http://www.cpslib.org/flaws/flaws.htm

I would like to add the placement-index to the XML data source 
programmatically. Is there a way to obtain the height or width of a jpeg 
image from the file itself (image.jpg, for instance) using XSLT? Or, can 
someone suggest another way to do this programmatically?

Feel free to wander around the website if you find it interesting.

Thanks,
Mark