Thumbnails don't display in product page

Hi there,
I've just upgraded to 1.6.
Now when I add an image to a product, the thumbnail doesn't display BUT it displays images that were already there prior to upgrade.
Here: horsewhispers.com.au/index.php/torsion-s...ld-standard-black-16

So the product already existed with some images. I just wanted to add new ones but they don't come up as thumbnails. However if you click on the image to start the slideshow, then they work ok.

In the admin back-end, they do show in the image section of the product page.

Thanks

Hi,

Can you just try to delete all the picture of this product and then add all of them ?

Hi Mohamed,
no I don't want to do that in case I can't get the photos back.

So I created a new product to test it instead.
at the time of the creation, I added the photos and saved it and they were fine. That is the thumbnails worked.
I then went back to the product and deleted the photos and added new ones. This is when it stops working. The thumbnails are broken.

yes I had to do some changes you gave me because there were some issues with them originally

I've removed the customisation and didn't reapply it and it's all working fine now