Using Xara all your images are reprocessed and numbered. I can see (by inspecting the image using firefox and also by looking at the page source) that you have added some alt tag values:

src="index_htm_files/84.jpg" alt="Human-Resources-HR-Consulting" id="Human-Resources-HR-Consulting" title=""

shows that image 84 has the alt tag set - so this will be read by Google. So you need to continue to do this for images that you have supplied.

You may also wish to fill in the mouse over popup text - this will then fill in the title too.

Paul