What is the cost of your non-responsive images?
JavaScript Shell
Pull request Compare This branch is 10 commits ahead, 21 commits behind yoavweiss:master.
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.



Node version of the wonderful Sizer-Soze project

What is the cost of your non-responsive images?

We've been talking about responsive images for years now, but what is the actual cost of delivering non-responsive images to narrow viewports? How many bytes are we sending for nothing?

@grigs wrote a blog post on responsive images breakpoints and their relation to a site's performance budget, which got me thinking: "We cannot manage a budget if we cannot measure costs".

So, I wrote this small script that measures a certain site in multiple viewports and outputs the bytes we can optimize losslessly and the bytes we can optimize if we'd tailor the images to this specific viewport.

Getting Started

Install the module with: npm install sizer-soze

var soze = require( './sizer-soze' );

soze.sizer( url, function( err, data ){
  if( err ){ throw err; }
  console.log( data );


Besides the summary results printed to screen, you can see detailed per-image results in your /tmp/ directory. Each tested site creates a directory there, and the original, optimized and resized images are stored there, as well as result logs per viewport.


  • image_optim
  • ImageMagick
  • curl
  • PhantomJS

How it works

  • run.sh simply iterates over 2 other scripts with several viewport sizes. Adding more viewports is simple, but it slows down the running time.
  • getImageDimensions.js is a phantomjs script that downloads the requested URL, and outputs all of its content images as well as their dimensions.
  • getResizedBenefits.sh is a bash script that gets the results of getImageDimensions.js, downloads the original images and resizes these images to see what their resized size is. It also optimizes the original images using image_optim, to see how much lossless optimization can get us.

Why bash???

I was aiming to minimize dependencies, so I went with bash. And well, now it's wrapped in Node.

What's with the name????

It's Saturday.


(Coming soon)


In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.

Release History

(Nothing yet)


Copyright (c) 2013 Jeffrey Lembeck & Yoav Weiss
Licensed under the MIT license.