The Pygments syntax highlighter apparently has support for multiple formatters including ImageFormatter for PNG output.
It would be helpful to others to mention it, since you're already mentioning other tools and their pros/cons.
sudo pip install pygments Pillow
pygmentize -O font_name='Andale Mono',line_numbers=false,font_size=16 -o whatever.png /path/to/file
The Pygments syntax highlighter apparently has support for multiple formatters including ImageFormatter for PNG output.
It would be helpful to others to mention it, since you're already mentioning other tools and their pros/cons.