Free software gave thumbnails; the wedding album needed full frames
Since the wedding the card had remained untouched (no additional frames had been added and no information had ever been written to it), and this is why the image of the card copied off so perfectly. Free software had previously tried to process these images and produced six hundred thumbnails, but none of them were good enough quality to print. Processing the scattered pieces of every CR3 image allowed all 640 to be rebuilt at full size.