WebP for all - not working as expected

[nacholibre]

I have a project with images in jpeg or png format.

I want to migrate all images to WebP format with a 301 redirect. My goal is to reduce image size without compromising quality and keep search engines ranking by doing a permanent 301 redirect.

According to the documentation doing this:

# app/config/config.yml

liip_imagine:
    default_filter_set_settings:
        format: webp

Should force all images to be converted to webp when any filter is used, however I'm not getting it. This option above does nothing.

I can get WebP images only if I include

# app/config/config.yml

liip_imagine:
    # configure webp
    webp:
        generate: true

But this causes generation of two images and resolving is called each time when an image is showed on a page. Even after the filtered image is created and the image is stored on the disk resolve is called each time. I'm assuming this is done to detect browser headers and support for WebP?

Also I'm noticing that images are bigger once when are converted to webp which is really odd? Filtered images are the same resolution.

total 648
drwxrwxrwx@ 10 nacholibre  staff   320B Jan 27 14:41 .
drwxrwxrwx@  6 nacholibre  staff   192B Jan 27 13:30 ..
-rw-rw-rw-@  1 nacholibre  staff   5.8K Jan 27 14:19 14434c84d296ccd05efb7580f3478ef1.png
-rw-rw-rw-@  1 nacholibre  staff    16K Jan 27 14:20 14434c84d296ccd05efb7580f3478ef1.png.webp
-rw-rw-rw-@  1 nacholibre  staff    68K Jan 27 14:19 5444edc8316cbd4c175acb1352186784.webp
-rw-rw-rw-@  1 nacholibre  staff   161K Jan 27 14:20 5444edc8316cbd4c175acb1352186784.webp.webp
-rw-rw-rw-@  1 nacholibre  staff    12K Jan 27 14:41 939c2a2427ef8ddef453aaa32702c11a.jpg
-rw-rw-rw-@  1 nacholibre  staff    21K Jan 27 14:41 939c2a2427ef8ddef453aaa32702c11a.jpg.webp
-rw-rw-rw-@  1 nacholibre  staff   6.4K Jan 27 14:19 d02cc7c2623b6fc1117bb11b8a3e18aa.png
-rw-rw-rw-@  1 nacholibre  staff    16K Jan 27 14:20 d02cc7c2623b6fc1117bb11b8a3e18aa.png.webp

$ file d02cc7c2623b6fc1117bb11b8a3e18aa.png: RIFF (little-endian) data, Web/P image, VP8 encoding, 300x300, Scaling: [none]x[none], YUV color, decoders should clamp
$ file d02cc7c2623b6fc1117bb11b8a3e18aa.png.webp: RIFF (little-endian) data, Web/P image, VP8 encoding, 300x300, Scaling: [none]x[none], YUV color, decoders should clamp

These tests are done on a local test environment with PHP 8.1, Symfony web server and imagine-bundle version 2.13.3.

My questions are:

• How to get all images converted to webp?
• Why are the webp images bigger than their jpg/png originals?

Thanks for your time building and supporting this library. I appreciate your efforts.