most likely the server is doing content negotiation and providing the more efficient image/webp version for the .jpg request since chrome supports webp.
(i.e., the browser is sending this header with the request:
Accept: image/webp)

are you using a CDN?

I will be accused of "tin foil hat" ... and I sometimes wear one ...

Chrome is a g product. Webp is a g product. JPG converted on the fly (thus keeping the user in the g garden). Nothing you can do about it ... not your stuff. Can't change it, force it, or much of anything else. Move on and deal with what you CAN control.

most likely the server is doing content negotiation and providing the more efficient image/webp version for the .jpg request since chrome supports webp.

Yes, I do the same: if WebP conversion produces a smaller image, I'll keep that alongside the original, e.g. picture1.png (6KB) and picture1.png.webp (5KB), and the web server will then serve WebP instead of PNG to supporting clients (without changing the file name in the request). This now works with most browsers except IE and Safari.

If you haven't set this up yourself, it's probably your CDN. Cloudflare does this with a feature called Polish. The process is described in more detail here: [blog.cloudflare.com...]

(Ignore the tin foil stuff above.)

Chuckles. :)

Experience indicates that the "additional" compression of webp at equal loss ratios is marginal ... and for ME keeping a pair (eating up storage) for which to send on broadband is a negative. Could be just me. :)

Chuckles. :)

same here.
so is it google (chrome) surreptitiously converting your jpegs on the fly or is it google (search) twisting your arm to store both jpeg and webp on your server?
it can't be both...

Actually, phranque, I believe that is exactly what is intended. G wins either way.

(sigh)

Personally I build my images EXACTLY the way I want them in the format desired ... and this "converting on the fly", even by cloudflare, is an irritant.

YMMV

.

Hello-

the extension of the images is JPG

The extension of a file is not the most important, it's the encoding of a file which matters. If you take a jpeg encoded image, and put .txt as the extension, it will still be a jpeg image.

That being said, if you are sure that your images are encoded in Jpeg at your server, it means that your server, your cdn, your proxy, (anything between you and the client) is re-encoding the file, certainly for speed delivery reasons. Webp images are smaller than their equivalent in Jpeg, in my case, it saves easily 25%, and it also has the advantage to have alpha transparency, the same way as PNG.

Chrome is a g product. Webp is a g product. JPG converted on the fly

I've never seen (so far) Chrome convering anything into a different format. Also, why? Chrome runs on the client side, so changing the compression of a file, once it was already transmitted is pointless. Chrome can "suggests" that it prefers a WebP format, when it sents its accept header, but it's still up to the server to send what it wants.