I use GIMP scripts for this. Instead of spreadsheet, just a call with arguments separated by commas like this:
(UrNammu-new-craftsman 1 "2Baubles.png" "Fleece the Tourist" "Got his pants! Gain 2 Baubles" "Google Images")
We print using thegamecrafter.com, which is a little struggle because our decks have 100+ cards, and they require EACH CARD to be 'proofed' by hand on their laggy webpage. Proofing 1 card is enough for our software-generated cards, they all align exactly the same vs the template.