Can I display more than 10 columns?
Do you support spreadsheet programs other than Excel?
The plug-in exports to CSV format which Numbers and OpenOffice can read, even if they can't read HTML
How do I set up other spreadsheet programs?
There's an option in File > Plugin Manager. Just point Excel to the other program's application / exe file.
Can I save export data to location other than the desktop?
Yes, it's an option in File > Plugin Manager
Why don't I see any thumbnails in Excel?
Have you exported the thumbnails? This is done separately from exporting the text.
The most-recent version of Excel for Mac fails to import thumbnails from HTML. This appears to be a bug in Excel.
Have you chosen HTML export? Thumbnails are only available in HTML export - comma-separated text can't include images.