Publié le September 15, 2022
Par Elodie Girard
Content manager, Greenmetrics

How does image optimization impact your carbon footprint?

TwicPics et Greenmetrics Analytics : un numérique durable et responsable

More and more data are delivered on websites

The median page weight increases over time, and the trend won’t change in the following years. According to HTTP Archive, “in the past decade, average Web page weight has grown a whopping 356 percent, from an average of about 484 kilobytes to 2,205 kilobytes.” The page weight went from 522KB on desktop, and 202KB on mobile in June 2011, to 2,202KB on desktop and 1,948KB on mobile in July 2021, thus an increase of four times on desktop and ten times on mobile!

Empreinte carbone : évolution du poids des pages

Accordingly, the Web’s carbon footprint is skyrocketing.

Media represent more than two-thirds of your page weight

Websites are heavier than ever, and the main culprits are visual assets. They eat up network bandwidth and increase the time visitors spend waiting for pages to load while being responsible for most of the carbon emissions on the Web.

Empreinte carbone : les médias représentent plus des deux tiers du poids des pages

Images remain the largest resource among HTML, CSS, JavaScript, and third-party resources.

The median mobile page has 877KB of images out of 1,440KB (total resources), and the median desktop page has 972KB out of 1,555KB. Thus images represent more than 60% of page weight on both mobile and desktop.

Therefore to eco-design a website, you must tackle down your media weight. Most of the time, people think it means sacrificing assets’ visual quality. But good news, there is a solution. Explanations.

Innovation to the rescue

With all kinds of devices, screen sizes, and pixel densities out in the wild, tailoring images or videos is extremely challenging. Fortunately, a new player is providing a game-changing solution with an innovative approach: TwicPics.

TwicPics is a Software as a Service that smartly automates the optimization of multimedia content on the Web.

Because TwicPics analyzes end-users context to deliver the right amount of data, the consumption of bytes exactly matches their needs. Nothing more than what they should receive but enough to get an optimal experience. TwicPics knows when, where, and how to crop and resize images.

In the end, TwicPics solution provides a developer toolkit to deliver eco-designed websites for the sake of digital sobriety. Moreover, since the sites are lighter, they are also faster to load. So it’s a win on all counts.

What’s the balance at the end of the day?

From their client’s perspective

It’s not new that calculating the carbon footprint of a website is not an easy task. Estimates for Internet energy consumption vary drastically. That’s why Greenmetrics exists. 

The elements to be taken into account to calculate the energy consumption related to the loading of a web page are divided into 3 segments:

  • Data-center usage: this is the energy needed to host and serve the data.
  • Network Usage: it is divided into 2 major segments, cellular and landline networks. Each has its proper consumption: the amount of energy necessary to load a page from a 3G/4G/5G network is far from being the same next to a Wifi.
  • Terminal Usage: it combines the energy used in the production and the use of the device, the duration of the visit imputed from the estimated lifetime of the device, and the complexity of the web page, as a blank and empty website will not use the same amount of energy as one filled with 1080p videos. 

Greenmetrics uses real-time data from Electricity Map to estimate the carbon intensity from the data center and the client’s perspective. It gives us the best-in-class estimation of the amount of CO2 emitted when browsing a website.

Combined with carbon intensity, Greenmetrics also uses the life cycle assessment of products to approach the real impact of browsing websites from the loading on a server to the viewing by the visitor.

It is important to remember that most of the carbon impact is on the user’s side:

  • Delivering lighter visual assets reduces carbon footprint while browsing the website.
  • Adapting the media to the end-users won’t over-saturate their devices and thus will positively impact battery and apparel life cycles.


TwicPics is reducing the data from visual assets by 45% on each customer’s website on average. Some have seen their consumption divided by 10!

Media are responsible for 60% of websites’ weight. So, in the end, their customers save 27% of data and as much CO2 on average.

A 1,000,000 monthly page views website can easily produce more than 5 TCO2e per year. That means 1 TCO2e could be saved each year in this case.

TwicPics is relatively new on the market, but we estimate they already have saved 2400 TCO2eq for 2021 alone. The equivalent of +21 818 000km in a diesel car. Almost 545 world tours!

TwicPics’ consumption

On the infrastructure side, they are not provisioning servers. Instead, their processing capacity adapts to needs in real-time, thanks to an auto-scaling mechanism. Without this strategy, the only option is over-provisioning servers to absorb load peaks. Again, it’s essential to keep in mind that the greenest energy is the one that is not consumed. According to the supplier dashboard, the TwicPics processing capacity made available to customers represents 0.8TCO2e over 2021 (including scopes 1 & 2).

At a time when the digital carbon footprint is soaring, it’s interesting to note that solutions such as TwicPics can provide concrete answers to the IT world.