Puppeteer wait for all images to load then take screenshot

There is a built-in option for that:

await page.goto('https://www.digg.com/', {"waitUntil" : "networkidle0"});

networkidle0 - consider navigation to be finished when there are no more than 0 network connections for at least 500 ms

networkidle2 - consider navigation to be finished when there are no more than 2 network connections for at least 500 ms.

P.S. Of course it won't work if you're working with endless-scrolling-single-page-applications like Twitter.

Another option, actually evaluate to get callback when all images were loaded

This option will also work with setContent that doesn't support the wait networkidle0 option

await page.evaluate(async () => {
  const selectors = Array.from(document.querySelectorAll("img"));
  await Promise.all(selectors.map(img => {
    if (img.complete) return;
    return new Promise((resolve, reject) => {
      img.addEventListener('load', resolve);
      img.addEventListener('error', reject);
    });
  }));
})