Encoding array of 8-bit RGB values to PNG

Hello,

I'm interacting with a scanner, and I have a contiguous block of memory 
containing 8-bit RGB data. I'd like to convert this to PNG, and I had a 
look at libspng but I'm not sure how to make it work with my current 
situation.

Could anyone give me some pointers or reading regarding this issue?

Regards,
rndusr