Hi,
By default, consuming a serial does not update the order ; so there is no order notification email send to the user.
If you want to send an order notification to send a new version of the "attach serial" image ; you have to have/create a consumption plugin to update the order or manually force the notification email.
But I have some difficulties to understand what your are trying to perform ; if you want to send the "attach serial" image afterwards, it means that in the first emails, before the serial is consumed, you don't want to include the image but you want to display the serial in the email (so the user will have the information to consume it).
Am I right ?
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.