I'm really not a wizard when it comes to developing web based applications but I did get a surprise in the way that Viart handles extensions.
I had a number of images that I had sized all but a few had xxx.JPG extensions. The remaining few had xxx.jpg (lowercase extensions. Talk about driving me nuts to figure out why Viart would not display them, it did
.
I have not made ALL of my 900 images correspond to uppercase extensions. I still have problems displaying the category images but at least I can see the images for the products.
Hope this helps avoid someone else from having problems.
Regards RLW