Since the introduction of WordPress 5.8 a year ago, users have been able to upload and use WebP images in their content, adding freedom. The Performance Team in March 2022 proposed that WordPress be able to enable WebP by default in the core to expand support for the image format. Among many things that can be done here is to generate WebP images for new JPEG uploads and use WebP images for the website’s content. However, following critical feedback, the controversial proposal was held in April.
In WordPress 6.1, only core image sizes are automatically generated as WebP versions by default, as opposed to all other image sizes. To receive automatic WebP versions, custom image sizes must first opt-in or opt out if they are exclusive to exceptional cases that WebP does not support.
To keep secondary (WebP) sub-sizes, they must be smaller than the primary MIME type if they are to be kept at all.
You should only generate WebP images for image sizes intended for use in front-end content that is visible to users. There is no need to store images in WebP format that you will never use, so this saves you storage space.
The generation of additional MIME types can be controlled by adding a filter based on the sub-size of an image. This allows the developers to restrict specific sizes of images used in the front-end content, such as those not used in the back-end.
Defaulting to WebP will only affect newly uploaded images after it has been incorporated into the core, so it will not affect current photos. Existing uploads would not automatically be converted to WebP when they are updated. WP-CLI or a plugin such as Regenerate Thumbnails would be the best option for users who want to convert past uploads into thumbnail images.
There has been a mixed response to the proposed revisions so far. However, it appears there is substantial support for the new approach, and other team members are encouraging the team to consider some of the practical implications for end users who could be affected by this change.
According to several commenters, WordPress should consider adopting the more modern AVIF format instead of its excellent quality and compression compared to the outdated design.
Moving to WebP support felt a bit like when WordPress added the REST API when everyone was transitioning to GraphQL simultaneously. It’s great to have REST and WebP, but they’re both current generation technologies, and they’ll feel stale pretty quickly.”