Pillow webp support

[Twilight0]

Package Information

• Package Name: webp
• PyPI Link: https://pypi.org/project/webp/
• Type: Native (C extension wrapping libwebp, libwebpmux, and libwebpdemux)

Description & Use Case

We need WebP image decoding and encoding support for mobile (Android/iOS) Flet apps.

Currently, on Android ARM64 builds, image processing libraries (such as Pillow or custom image pipelines) lack the underlying libwebp shared libraries and C bindings, resulting in UserWarning: image file could not be identified because WEBP support not installed when reading WebP images downloaded from CDNs (such as Instagram, Facebook, and modern web services).

Adding webp (or compiling Pillow with libwebp enabled in the serious-python/python-build toolchain) will allow seamless WebP image reading, writing, and processing on mobile.

[ndonkoHenri]

WebP is now supported in pillow on Android and iOS: https://pypi.flet.dev/pillow

Nothing to change in your app — same version, so a rebuild picks it up:

dependencies = [
    "flet",
    "pillow",
]

Image.open() on a .webp now works, and so does saving one: lossy and lossless, alpha, EXIF, and animated WebP frame by frame.

Note

We did not add the webp package you linked, because it would not have fixed the error you hit. It registers no PIL plugin, so PIL.Image.open() would still have raised. The real gap was that our pillow was built without libwebp — now shipped as flet-libwebp and linked in. If you specifically need pywebp's byte-budget encoding (WebPConfig.target_size), open a new request and we'll look again.

One thing worth knowing for your CDN case: displaying WebP already worked. ft.Image(src=<url>) hands the URL to Flutter, whose decoder supports WebP and animated WebP natively — no Python involved. What was broken was processing those bytes through Pillow, which is what this fixes.

Give it a try and let us know! 🤟🏿

[Twilight0]

Thank you!