S100 - what is maximum GB SD memory card?
Page 16 of the owner's manual states:
The cards below can be used without restrictions on their capacities.
SD memory cards
SDHC memory cards
SDXC memory cards
There is what I suppose to be a typical disclaimer to the effect that some cards may not function properly depending on the brand.
As long as they comply with SD standards, they should work.
In case you didn't know, you can go to the Canon USA site & download the owner's manual. It is a protected file that will not allow copying or printing.