Hi,
As I said, please check the product in your backend.
It is not just the thumbnails which are not generated, the image path is not good and hikashop also use the default image for the full image (when you click on the thumbnail to open the lightbox).
So please, check in the backend ; your image might be added fine, the added content is not.
Maybe you added some extra spaces in the filename, maybe it's not the right path...
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.