Hi,
Does the FTP really necessary ?
I guess that is the source of your problem.
HikaShop uses Joomla to write the image in your website (JFile::write). After that Joomla will use his configuration to write it.
But we do not said anything on file permission, the component just ask Joomla to write the file. So it is something to modify in your FTP configuration.
There is nothing to do in HikaShop.
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.