Hi,
HikaShop business have "item custom fields" that could you make this upload feature.
The "item custom field" is an information that the customer will set on the product in the cart. It can be some text or it can be an image.
You can read more about item custom fields in our documentation and you can test it directly in our demo website.
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.