Snapshot image quality issue

Steps to reproduce

Tell us about your environment:

• Puppeteer version: 0.13.0
• Platform / OS version: Ubuntu 16.04 LTS
• URLs (if applicable):

What steps will reproduce the problem?

  const browser = await puppeteer.launch({
    args: ['--no-sandbox', '--disable-setuid-sandbox'],
  })
  const page = await browser.newPage();
  page.setViewport();
  await page.goto(
    `data:text/html;charset=utf-8;base64,${new Buffer(htmlString).toString(
      'base64',
    )}`,
    {
      timeout: 120000,
    },
  )
  await page.screenshot({
    type: 'png',
    path: outputFileName,
    fullPage: true,
  })

As you may be able to see below, the quality in image 1 is significant higher than that of image 2. There are blurry edges on both the words and images within the snapshot, I am wondering if there are ways to increase the quality of the snapshot image using puppeteer without increasing the deviceScaleFactor, as I need the images to be of specific dimensions.

on Windows PC using chrome to render the HTML and screenshot snipping tool (image 1): snapshot using puppeteer on Ubuntu (image 2):

[chunsli]

Side note, we tried node-sharp as well, the scaled down image quality is not good enough as well.

[KyleGoddard]

having the same issue.