Hey, thanks for the suggestion. I've used Pygments in the past and didn't even think to check if it had a PNG output mode.
Here's an example of Pygments C++ output: http://imgur.com/a/7TbMb
And the same file through Prism.js + Puppeteer: https://github.com/mplewis/src2png/blob/master/docs/arduino....
Pygments does a great job of generating detailed PNGs. The default settings aren't quite what I'm looking for, but they look like they could be tweaked to increase the resolution and change the color scheme.
I'm embedding my examples in a Keynote deck, so I'm picky about font family, size, resolution, etc. I bet I could get similar results by writing a custom script for Pygments. Thanks for sharing!