This might help anyone struggling with webkit2png which is outdated and broken on a lot of websites. This python script uses headless chrome and only scratches the surface of what is possible. Thanks to https://gist.github.com/rverton/d07a2232f4c0e1c2b9894e9bdb4fa6cf for inspiration.

chrome_headless_screenshot.py

# Adapted from: https://gist.github.com/rverton/d07a2232f4c0e1c2b9894e9bdb4fa6cf
#
# Install:
#   chromedriver from https://sites.google.com/a/chromium.org/chromedriver/downloads
#   Python deps (pip or pipenv): `pipenv install click selenium`
#
# To use:
#   python chrome_headless_screenshot.py --height=1280 https://jefftriplett.com/ screenshot.png

import click

from selenium import webdriver


CHROME_PATH = '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome'
CHROMEDRIVER_PATH = '/usr/local/bin/chromedriver'


@click.command()
@click.option('--width', '-W', default=1024)
@click.option('--height', '-H', default=1024)
@click.argument('url')
@click.argument('output')
def make_screenshot(url, output, width, height):
    if not url.startswith('http'):
        raise Exception('URLs need to start with "http"')

    chrome_options = webdriver.ChromeOptions()
    chrome_options.add_argument("--headless")
    chrome_options.add_argument("--window-size={width},{height}".format(width=width, height=height))
    chrome_options.binary_location = CHROME_PATH

    driver = webdriver.Chrome(
        executable_path=CHROMEDRIVER_PATH,
        chrome_options=chrome_options
    )
    driver.get(url)
    driver.save_screenshot(output)
    driver.close()


if __name__ == '__main__':
    make_screenshot()