When saving Excel 2007 workbooks in the Excel 2003 format, they will
frequently expand significantly. Recently a 9 mb Excel 2007 file expanded to
more than 52 mb when saved as an Excel 2003 file. The only research that
I've been able to locate on this topic discusses "thememanager.xlm" that gets
included in the 2003 file and greatly expands its size.

Does anyone have any ideas about this, and specifically about how to prevent
it? We frequently need to convert files back to 2003 format for our clients,
and it's problematic when they grow this big.

Thanks.