Google Lighthouse incorporates AVIF into its recommendations for optimizing websites, in addition to other modern image formats, providing significant savings in file size thanks to the inclusion of AVIF.
Google Lighthouse and Google PageSpeed Insights have been recommending the use of modern file formats, such as WebP and JPEG 2000, for many years.
Their primary benefit is that they tend to have smaller file sizes than traditional formats, such as PNG or JPG, for similar quality images.
Another modern file format that offers substantial potential savings is known as AVIF, also known as AV1 Image File Format. This format allows for both lossless and lossy compression. Thus, it is ideal for reducing the size of images and thereby reducing the load time of websites.
The Google Lighthouse incorporates AVIF into its recommendations, and that's in the section "Provide images in modern formats".
Each BMP, JPEG, and PNG image on the page is collected by Lighthouse, converted to WebP, and an AVIF file size estimation is performed, reporting the potential savings.
Image formats such as AVIF and WebP have superior compression capabilities and image quality compared to older formats such as JPEG and PNG. Your images will load faster and consume less data if you encode them in these formats rather than JPEG or PNG.
In comparison to other formats with the same quality settings, AVIF offers smaller file sizes due to support in Chrome, Firefox, and Opera.
Future usage of AVIF could provide a good alternative to existing file formats, thereby reducing the loading time of websites. However, as not all browsers support AVIF, an alternative should be offered.