i had a functional shopping site with joomla Joomla! 2.5.4 & virtue mart 2.0.6 .
when user browse a product, product image is not displayed if a single image is uploaded.
but product images are displayed if multiple product images are uploaded.
expert support needed to identify the issue.
Both your joomla and vm are totally out of date and therefore a security risk
The image problem sounds template related
http://forum.virtuemart.net/index.php?topic=118683.0