PNG not converted to webp

So you say that cwebp converts JPG, but fails converting PNG?
No-one has reported that before. Thanks for reporting!
Can you tell me exactly what happens?
My guess is that cwebp is simply skipped for PNGs, and the next converter can try.

I have on my roadmap to test PNG conversions better. The tests should also show PNG, and there should be warnings next to the converters that may have issues with PNG, when PNG is activated.

Do you really experience Gd compressing better than cwebp?
My experience is that cwebp performs slightly better.

Would a “skip png” checkbox in all the individual converter options be an improvement to you?

Yes, cwebp converts JPG, but fails converting PNG.

No errors, when I see “network” in the Type column I see that png are not converted in webp

I don’t know if “skip png” will be an improvement. I never see how it works with png.

Gd compression is a bit better but it could be because with cwebp the quality option was not changing anything. Or it could be that with php 7.3 gd is improved.

Hm, it sounds like the redirect isn’t working for PNG. To test if redirect is working, please examine the response headers, and see if there is a X-WebP-Convert response header (if you don’t know how to do that, check out the verifying that the plugin works-section in the FAQ).

So, is there a X-WebP-Convert response header for the PNG’s, and what does it say?

I don’t find how to see response header for each image in FAQ.

if it can help these are my response headers with gd.

date Mon, 10 Dec 2018 11:48:55 GMT
server Apache
link ; rel=”https://api.w.org/”
x-frame-options sameorigin
referrer-policy no-referrer-when-downgrade
x-xss-protection 1; mode=block
x-content-type-options nosniff
vary Accept-Encoding
content-encoding gzip
strict-transport-security max-age=31536000; includeSubDomains; preload
content-length 15313
content-type text/html; charset=UTF-8

1. Open the page in Google Chrome
2. Right-click the page and choose “Inspect”
3. Click the “Network” tab
4. Reload the page
5. Click on a PNG image

You should see response headers there

using cwebp

Some png are converted and so I see: x-webp-convert-status: Serving existing converted image

When they are not converted I see: Serving original image (it is smaller than the already converted)

• This reply was modified 5 years, 11 months ago by efilippucci.

Ok, then everything seems to be working as it should ??

Except that it is disappointing that cwebp cannot do better with png. Perhaps it can be improved by tweaking the cwebp options. I have created an issue for it in github: https://github.com/rosell-dk/webp-express/issues/101

Marking as resolved, as the cause have kind-of-been found. I will follow up here, when I get to investigate this further.

Thanks a lot ??

Now there is cwebp 1.0.1 but I don’t know if it is stable on Ubuntu.

I have seen that apparently no one is using it on Ubuntu.

I tested now with cwebp 1.0.1 and webp express 0.8.1.

There is not difference, most of the png are not converted since the original version is smaller

im getting x-webp-convert-status: Failed (No converters could/wanted to convert the image) with all of my png images

@ezzmay007: That is probably because you have the “Skip pngs” option set on the Gd converter. That option is on per default, because it seems Gd has problems with transparency: https://github.com/rosell-dk/webp-convert/issues/42