WebP, an image format developed by Google intended to replace the JPEG, PNG and GIF file formats, will soon be generated as default for new JPEG image uploads in WordPress and used for website content. The main work for this feature has been handed over to the core to be included in the upcoming WordPress 6.1 release.
The initial proposal was revised after significant critical feedback. The most notable changes include auto-generating WebP versions of only major image sizes, keeping secondary (WebP) sub-sizes only if they are less than the main MIME type, and generating WebP images only for sizes images for use in the user. facing front-end content.
Despite a series of revisions and filters to control or disable WebP downloads, the proposal remained controversial. Contributors continue to report issues after testing. Many still have reservations about whether this should be opt-in or enabled by default.
“When converting medium resolution photographs (about 1600px – 2500px on the long edge), WebP files are often larger than the JPEG equivalent,” WordPress developer Mark Howells-Mead commented on the main ticket for the WebP work. “(In my tests using my own photography, about 60% of the time.) This change might make Page Speed Insights’ “modern aspect ratio” test happy, but the default WebP app on sites that use a lot of photography will often cause longer image load times.
Some developers support the change but prefer it to be disabled by default when first deployed, to allow the ecosystem to prepare for the change.
“I really see it as a big benefit to add Core support for additional MIME types for small image files,” said Matthias Reinholz. “But I don’t see adding converting to another specific file format as a preferred behavior. This may help optimize WebP’s market position, but it will also pose a serious threat to plugin authors and developers. large existing websites that do not pay attention to this change.
“Therefore, I wonder why this feature should be enabled by default at this point. IMHO, it should only be an opt-in. Also, ideally, we would already start thinking about adding other image formats to be supported by this feature.
NerdPress founder Andrew Wilder created a separate ticket urging contributors to consider enabling the feature, but the ticket was closed and the conversation was redirected to the main ticket so as not to split the discussion.
“Making these new features opt-in rather than opt-out would be the best way to be cautious about potential impacts,” Wilder said.
“There have been many requests for this to be opt-in (as well as some asking for a setting on the Media page, rather than just a filter for developers). So far there has been no open conversation about why this is not being considered.”
The idea that default WebP should be opt-in was summarily dismissed and the conversation was not revisited until the changes were committed.
“The feature will have many benefits for users opting into the base sizes (to start) – if fully opt-in it would have little impact – or benefit,” said Adam Silverstein, lead sponsor of Google, in response to opponents.
In response to suggestions that this feature comes with a UI to enable it on the media page, Silverstein said, “We discussed both suggestions in chats and issues with mixed responses. The philosophy of the project is regularly mentioned as aligning with the current approach.
The ticket remains open pending fixes for some loose threads on the technical implementation. Contributors continued to raise additional concerns.
The Performance team has a new blog where people can follow updates on their current projects and proposals. Now that core WebP work has been committed, next steps will be discussed in future meetings with notes posted on the new Core Performance blog.