Serve Images in Next-Gen Formats

Question

My ranking from Google Page Speed insights is being severely penalised because of:

"Serve Images in Next-Gen Formats" more info on Google's help page here.

However, according to this, this and this those formats are supported very few browsers.

What do you do in this scenario? What

Answer 1

You could use the <picture> element to deliver a WebP image to users with browsers that support it, falling back to a JPEG or PNG for those that don't. The advantage of using the <picture> element rather than other fallback methods is that browsers that don't support the element will fallback to whatever source is defined in the <img> tag.

<picture>
  <source srcset="img/yourImage.webp" type="image/webp">
  <source srcset="img/yourImage.jpg" type="image/jpeg"> 
  <img src="img/yourImage.jpg" alt="Your image">
</picture>

Here's a method for converting source images to WebP.

If you're using WordPress there are plugins that will automatically generate WebP images from your media library and include fallback functionality. The only one I've used is WebP Express but it served me reasonably well when a client was alarmed that their 100/100 PageSpeed Insight score took a nosedive to 30 overnight with the Lighthouse roll-out.

This does feel like another way for Google to push another propriety technology but then WebP compression is quite impressive compared to other 'next-gen' formats.

Answer 2

WebP is the one that currently has broader support, pretty much all major browser except Safari support it.

As colossalyouth mentioned on one of the answers you can use the picture tag to load webp images and in the case is not supported it will fallback to any other format you choose.

And if you are using background-image you can use something like modernizr to detect feature support by the browser and end up with CSS like the following:

my-selector {
    background: url('../images/home-bg.webp') no-repeat scroll center center
}

.no-webp my-selector {
    background: url('../images/home-bg.jpg') no-repeat scroll center center
}

I have actually done both things on my website and successfully implemented webp formats, I have created a detailed post on how I did it and the performance gains I had you can check it out here: Improve your website speed performance using next-gen formats

Answer 3

Until major browsers support those next-gen formats, it's probably best to continue using JPG/PNG, as they have wide-spread support. Most websites do indeed use JPG & PNG and it will take some time till browsers are in-line with next-gen tech.