Webp images distort in image pipelines

[sniafas]

Description

When a .webp image enters the convert_image routine, it gets distorted adding a black background.

Steps to Reproduce

1. Get a webp image
2. Run a the pipeline
3. 

Expected behavior: An image without the blacked background

Actual behavior: A distorted image

Reproduces how often: Everytime for .webp images

Versions

Please paste here the output of executing scrapy version --verbose in the command line.

2022-12-20 13:03:32 [scrapy.utils.log] INFO: Scrapy 2.5.1 started (bot: banners)
2022-12-20 13:03:32 [scrapy.utils.log] INFO: Versions: lxml 4.9.1.0, libxml2 2.9.14, cssselect 1.2.0, parsel 1.7.0, w3lib 2.1.0, Twisted 22.10.0, Python 3.9.1 (default, Jun  7 2022, 16:18:41) - [GCC 9.4.0], pyOpenSSL 22.0.0 (OpenSSL 3.0.7 1 Nov 2022), cryptography 38.0.4, Platform Linux-5.14.0-1054-oem-x86_64-with-glibc2.31
2022-12-20 13:03:32 [scrapy.utils.log] DEBUG: Using reactor: twisted.internet.epollreactor.EPollReactor
Scrapy       : 2.5.1
lxml         : 4.9.1.0
libxml2      : 2.9.14
cssselect    : 1.2.0
parsel       : 1.7.0
w3lib        : 2.1.0
Twisted      : 22.10.0
Python       : 3.9.1 (default, Jun  7 2022, 16:18:41) - [GCC 9.4.0]
pyOpenSSL    : 22.0.0 (OpenSSL 3.0.7 1 Nov 2022)
cryptography : 38.0.4
Platform     : Linux-5.14.0-1054-oem-x86_64-with-glibc2.31

Additional context

Any additional information, configuration, data or output from commands that might be necessary to reproduce or understand the issue. Please try not to include screenshots of code or the command line, paste the contents as text instead. You can use GitHub Flavored Markdown to make the text look better.

[wRAR]

Old PR about this issue: #3072