There is a lot of options and they all have their pro and cons.

Option 1: Use an API

• ApiFlash (based on chrome)
• EvoPDF (has an option for html)
• Grabzit
• HTML/CSS to Image API
• ...

Pros

• Execute Javascript
• Near perfect rendering
• Fast when caching options are correctly used
• Scale is handled by the APIs
• Precise timing, viewport, ...
• Most of the time they offer a free plan

Cons

• Not free if you plan to use them a lot

Option 2: Use one of the many available libraries

• dom-to-image
• wkhtmltoimage (included in the wkhtmltopdf tool)
• IMGKit (for ruby and based on wkhtmltoimage)
• imgkit (for python and based on wkhtmltoimage)
• python-webkit2png
• ...

Pros

• Conversion is quite fast most of the time

Cons

• Bad rendering
• Does not execute javascript
• No support for recent web features (FlexBox, Advanced Selectors, Webfonts, Box Sizing, Media Queries, ...)
• Sometimes not so easy to install
• Complicated to scale

Option 3: Use PhantomJs and maybe a wrapper library

• PhantomJs
• node-webshot (javascript wrapper library for PhantomJs)
• ...

Pros

• Execute Javascript
• Quite fast

Cons

• Bad rendering
• No support for recent web features (FlexBox, Advanced Selectors, Webfonts, Box Sizing, Media Queries, ...)
• Complicated to scale
• Not so easy to make it work if there is images to be loaded ...

Option 4: Use Chrome Headless and maybe a wrapper library

• Chrome Headless
• chrome-devtools-protocol
• Puppeteer (javascript wrapper library for Chrome headless)
• ...

Pros

• Execute Javascript
• Near perfect rendering

Cons

• Not so easy to have exactly the wanted result regarding:
  • page load timing
  • viewport dimensions
• Complicated to scale
• Quite slow and even slower if the html contains external links

Disclosure: I'm the founder of ApiFlash. I did my best to provide an honest and useful answer.

Yes. HTML2Canvas exists to render HTML onto <canvas> (which you can then use as an image).

NOTE: There is a known issue, that this will not work with SVG

May I recommend dom-to-image library, that was written solely to address this problem (I'm the maintainer).
Here is how you use it (some more here):

var node = document.getElementById('my-node');domtoimage.toPng(node)    .then (function (dataUrl) {        var img = new Image();        img.src = dataUrl;        document.appendChild(img);    })    .catch(function (error) {        console.error('oops, something went wrong!', error);    });