Hello Raoul,

unpublishing the content data source all the articles urls will be excluded, if you want to keep some urls you can exclude specific categories or single articles only.

int he images sitemap there are not duplicates, there are same images found in different links like this: http://www.hollandhardware.com/images/content/pijl.png

The image is present in more than one page and probably should be excluded because it's not interesting for indexing, this image probably is more suitable: http://www.hollandhardware.com/en/cisco-en/cisco-catalyst-3750-series

The canonical link to generate sitemap that have to be added to robots.txt is this: http://www.hollandhardware.com/index.php?option=com_jmap&view=sitemap&format=images&lang=en

When you open it in your browser having multilanguage enabled Joomla redirect using a 301 to this url: http://www.hollandhardware.com/en/?option=com_jmap&view=sitemap&format=xml&lang=en

but this won't affect search engines thanks to the JSitemap plugin, it ensures that also search engines like Bing that doesn't support 301 redirects will be able to fetch the sitemap.

Regards

John