Hi,
The upload in HikaShop/HikaMarket is not in the same folder than the Joomla media manager.
When Joomla uses the "images" folder, HikaShop uses the "media/com_hikashop/upload" one.
HikaMarket create one folder per vendor, so the images/files for the different vendors are stored in different folders.
You said that the upload has failed but, is the file stored in the server ?
Do you have the vendor directories under the "media/com_hikashop/upload" folder ?
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.