Allow more preview formats

[rullzer]

Right now we serve previews in png or jpg. Which has the advantage of being support on nearly every platform since the late 90s. But of course it is no longer the best solution out there.

I would propose to allow different image formats. The top candidate in my opinion is webp. This allows for smaller images at comparable quality. Of course the backend would need to distinquis what to server but I'm sure we can solve that with some js magic to set the accept headers ;)

This doesn't mean we fully get rid of the jpg an png as older firefox and IE versions do not support it. But I bet this could be performance boost especially when using a lot of images.

[lapineige]

👍 for WebP, it is now supported by the major web browsers, and is more interesting than JPEG, PNG and GIF if we look at the quality/file size.

I think that would be a nice addition, for instance for people who wants to save some storage space on their servers thanks to WebP, for a galery of pictures, and so on.
And images in this format would speed up page loading (smaller file size).

[MorrisJobke]

ref #9857

[stale]

This issue has been automatically marked as stale because it has not had recent activity and it seems to be missing some essential informations. It will be closed if no further activity occurs. Thank you for your contributions.

[J0WI]

There is a tiny app for WebP support written by @Flow86:
https://github.com/Flow86/preview_webp

Would you agree to merge this functionality upstream?

[Flow86]

yes of course you can merge the functionality to upstream

[stefaang]

Here's an interesting demo with blurred webp preloads: https://jmperezperez.com/webp-placeholder-images/