Hi,
hmm interesting. I don't have any clue about what might cause it. I have never seen something like this before.
But modules acts very simple and naive in most of cases. Because they are mostly using 1-PHP line to gather the information from the components;
In this case, our module uses this line below to gather the product thumbnail from Virtuemart:
$image = $product->images[0]->displayMediaThumb('class="FlexibleCarouselPictureImg" border="0"',false) ;
This is the official line that has also been used by Official VM Module (VM - Featured Products Module) and the
displayMediaThumb() is a function that has been defined in the Virtuemart core files. So nothing is wrong here.
If the PHP line or the usage is broken, it will be broken for all of item (not for some of them).
If gathering pictures work for some products, but won't work some others. Then it must be because of something deeper, instead of a ordinary coding error.
Did you try to remove the product picture, and re-uploading it?
Regards,
Support