Hi,
That, or you changed something else since the backup, or you had some custom code in HikaShop related to the images, and you lost that custom code with the update and thus it's behaving differently.
However, as I said, if you have the file /images/com_hikashop/upload/thumbnails/600x600f/quinta-das-lamelas-2015-vintage.jpg
And when you access it with your browser, it can't load it, it's not something done by HikaShop but by the server:
i.imgur.com/L2RqNxY.png
Do you have the file /images/com_hikashop/upload/thumbnails/600x600f/quinta-das-lamelas-2015-vintage.jpg if you check via FTP ?
If you do not, then it's likely that the "upload folder" setting of the HikaShop configuration is wrong and thus HikaShop is generating a wrong URL for the images.
If you do have it but the server doesn't provide it when requested, then I don't see how it can be linked to HikaShop, or the update.