Hello,
Just like the "max_file_size", you can add an option "allowed_extensions" to the array structure in order to override the default setting.
When you're uploading an image, the HikaShop configuration setting for image extension is used.
And when you're uploading a file (not an image), it's the HikaShop configuration setting for the file extensions.
So with the new trigger that I will add into HikaMarket, you will also have the possibility to add your custom behavior.
But, I do like the idea of having new "Access Level options" in HikaMarket for these upload restrictions ; so I think that I will work on them for a future release too !
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.