How does the Smart card (Access on Card / Secure Credential Card) store the templates on the card?

Normally in Suprema devices each finger is made up of 2 fingerprint templates. 
Each template is 384 bytes by default when it's stored inside the device. 
However, when writing a template on the card, only 1 template is stored to take into factor the small storage space of the card. 

Can I change the fingerprint template size smaller than the default 384 bytes? 
BioStar 2 also provides an option to trim the last part of the template which is normally blank. 
You can reduce the size to up to 300 bytes to store the templates in a limited card's memory.

How many fingerprint templates can I store in a card?

You can store 2 fingerprint templates on one 1K card. 

For a 2K card you would be able to store 4 fingerprints. 

Can I store Face templates in a card?

Unfortunately, no. Face templates are too large to be stored in a card.