Problem with images visualization

Hi all!
In my work site www.ferramentacicerogaetano.it , I'm using the hot scroller VM module to preview products. Since I upgraded the module can no longer view thumbnails but clicking on the name of the product you are still unable to reach the affected page.
Also I would like to ask how to change the color of the Add button, Cart, as I have tried several times to change the color code but it does not work, the color remains the same.
The Joomla version used is 2.5.14 and the Virtuemart version is 2.0.22a
Please can someone help me?
Thank you

Yes but some of them work normally (I checked some washing machine) so maybe resting images in product edit page may help

Yes, you are right, some of them work but them work only because I inserted them time ago, before update... After update it's that result.
All pictures have the same extension (.jpg) and the same dimension (600*800). I don't know what else I can do to restore visualization...

Do you have main image and at least one additional image set for that new products

Hi Ivan!
Yes I have main image in the article, if you go on my website Ferramenta Cicero Gaetano and click on one of first five products, you can see that main image are already put on. The only problem is that the module Hot scroller doesn't work good.
I use that module to show to my customers the preview of all products so they can find easily that they need.
Please help me to solve this problem

Send admin access using "Report To Moderator" so I could check that products.