Andrea Verlicchi - Blog

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Images optimisation 4.0, a user-driven approach. A talk on automating your workflow with responsive images @ CSS Day (IT) 2022

On April 1st 2022 I spoke about responsive images optimisation 4.0 at the CSS Day 2022 Conference in Faenza, Italy. The speech was on how to improve performance on your website by automating responsive images.

How to integrate git in Mac OS Terminal (shell)

Now that zsh is the default shell on Mac OS terminal, you might want to setup you new Mac or VS Code terminal to have a smart integration with git, something similar to git bash for Windows.

An elegant technique to lazyload images in Swiper, and lazily create Swiper instances

Say you have multiple carousels in a page, each one containing multiple images, and you want to download only the images that are inside the visible portion of the page, and maybe save some CPU time by lazily create the carousel instances. I think I’ve found a valuable and elegant technique to do so.

vanilla-lazyload vs lazysizes

As the author of vanilla-lazyload, it’s not the first time I get asked the question: What are the differences between vanilla-lazyload and lazysizes? This blog post is the answer to that question.

Quicklink case study: faster pages, increased page views

QuickLink is a lightweight library created by Addy Osmani (Google) that prefetches pages linked to the current page, as the links to those pages enter the visible portion of the page (viewport).

aspect-ratio: A modern way to reserve space for images and async content in responsive design

To avoid layout shifting and optimize for the Cumulative Layout Shift web vital in you web pages, you need to reserve space for any content that might be rendered later in time. This is the case for images, videos and any asynchonously loaded content (e.g with AJAX calls). Here’s a new way to do it.

A clever way to serve WebP images to modern browsers and JPG to IE

Before the day Safari started support WebP images, we were forced to use the picture tag to serve WebP images to browsers supporting it. Today all modern browsers support WebP, so there’s probably a clever way to do that using a single tag: img.

How to cap image fidelity to 2x and save 45% image weight on high-end mobile phones

With the rise of very high density “super retina” displays in the newest high-end devices, capping image fidelity to 2x leads to a big improvement in terms of rendering speed, and no perceivable quality loss for your users. Here’s a new best practice on how to do that.

How to optimise for CLS when loading more content asynchronously

Cumulative Layout Shift (CLS) is an important, user-centric metric for measuring visual stability because it helps quantify how often users experience unexpected layout shifts — a low CLS helps ensure that the page is delightful.

Lazy load responsive images in 2020

Do you want to boost performance on your website? You can do that by using responsive images and lazy loading! In this article, you will find the HTML, JavaScript, and CSS code to lazy load responsive images, to make browsers use modern image formats like WebP and Jpeg2000, and to enable native lazy load where supported.

How to productively use the new Chromium-based Microsoft Edge browser

Here’s a practical guide on how to productively use the new Chromium-based Microsoft Edge browser: download it, change the default search engine, install extensions, and more.

Critical CSS with Jekyll and SASS

This site is run by Jekyll on GitHub pages and its CSS is built using SASS. Today I decided to boost performance even more inlining the render-blocking critical CSS, but even searching the internet I struggled to find an easy way to do it. This post is for you, in case you want to do the same.

Web Share API, the step after PWA

Today I experimented with the Web Share API and implemented it on this website, just to begin. Here’s what I did and how you can implement it on your website.

This website is now a Progressive Web Application

Some of my workmates and I took part to a Google Hackathon about Progressive Web Application and we learned a lot, so I’ve decided to enable this website as a PWA. Here’s what I did…

A smashing article on hybrid lazy loading

On May 6th, 2019 I wrote my first article on Smashing Magazine: Hybrid Lazy Loading: A Progressive Migration To Native Lazy Loading.

Native lazy loading and js-based fallback with vanilla-lazyload 12

On April 6th 2019, Addy Osmany wrote about native image lazy-loading. Two days later Yvain, a front-end developer from Paris, asked me if my vanilla-lazyload could be a loading attribute polyfill, inspiring me to develop and release version 12 of the script, which features a new use_native option to enable native lazy-loading where supported. You can already use it today.

Detect IntersectionObserver with an online tool

Today I updated my iPhone to iOS 12.2 beta 4 which features the new version of Safari (also 12.2) with support to the IntersectionObserver API. I wanted to see it clearly so I’ve created a web page that detects and reveals to you if it’s supported.

Responsive and accessible table design

How to make a potentially wide table fit on small devices, without losing readability and accessibility? Here are simple solutions to make tables look like lists, lists look like tables, in responsive and accessible design.

Lazy load responsive images in 2019

In the latest years, both at my job and as maintainer of a LazyLoad script, I’ve specialized in lazy loading of responsive images. Today I’m going to show you what HTML, CSS and JavaScript code you need to write in 2019 in order to serve responsive images and load them lazily. In the second part of the post, I’m also showing how to make the browser natively pick the WebP image when it supports it.

My notes from Full Stack Fest Barcelona

I just returned from Barcellona where I attended the Full Stack Fest Conference, which was I think the best one I’ve ever attended in the latest years.