SUMMARY While Krita has no problem dealing with webp files, it only allows saving them as low quality lossy, when format allows for lossless, various levels of quality lossy and different encoding options.
It's a minimal solution, but a quality setting is in master already, because it annoyed me too: https://invent.kde.org/kde/krita/commit/5939f1315fbd952a82c434beb6e2c7a33d4f9b78 The Qt WebP image I/O plugin unfortunately is very minimalist too, so for things like separate alpha quality and the various filtering options it'd need a dedicated export plugin using libwepb directly.
A possibly relevant merge request was started @ https://invent.kde.org/graphics/krita/-/merge_requests/891
Git commit 0d811d3464a8ba10f3c8dc705a302f030326a73d by L. E. Segovia. Committed on 18/07/2021 at 18:04. Pushed by dkazakov into branch 'master'. WebP: add libwebp based file format plugin This commit incorporates a new file format plugin based on the official libwebp codec. It also brings new import/export dialogs that enable access to all the available configuration parameters in libwebp as of 1.20. (I have ifdef'd the most recent bits so it should compile with the latest LTS release.) CCMAIL: kimageshop@kde.org M +2 -0 3rdparty/CMakeLists.txt A +25 -0 3rdparty/ext_webp/0001-Fix-CMake-targets-install-directory.patch A +15 -0 3rdparty/ext_webp/CMakeLists.txt M +12 -0 CMakeLists.txt M +1 -1 build-tools/windows/build-msvc.cmd M +1 -1 build-tools/windows/build.cmd A +224 -0 cmake/modules/FindWebP.cmake M +1 -0 packaging/android/androidbuild.sh M +1 -0 packaging/linux/appimage/build-deps.sh M +1 -1 packaging/macos/osxbuild.sh M +4 -0 plugins/impex/CMakeLists.txt M +2 -2 plugins/impex/qimageio/krita_qimageio_export.json M +2 -2 plugins/impex/qimageio/krita_qimageio_import.json A +27 -0 plugins/impex/webp/CMakeLists.txt A +166 -0 plugins/impex/webp/dlg_webp_export.cpp [License: GPL(v2.0+)] A +28 -0 plugins/impex/webp/dlg_webp_export.h [License: GPL(v2.0+)] A +822 -0 plugins/impex/webp/dlg_webp_export.ui A +181 -0 plugins/impex/webp/dlg_webp_import.cpp [License: GPL(v2.0+)] A +54 -0 plugins/impex/webp/dlg_webp_import.h [License: GPL(v2.0+)] A +421 -0 plugins/impex/webp/dlg_webp_import.ui A +237 -0 plugins/impex/webp/kis_webp_export.cpp [License: GPL(v2.0+)] A +29 -0 plugins/impex/webp/kis_webp_export.h [License: GPL(v2.0+)] A +191 -0 plugins/impex/webp/kis_webp_import.cpp [License: GPL(v2.0+)] A +32 -0 plugins/impex/webp/kis_webp_import.h [License: GPL(v2.0+)] A +72 -0 plugins/impex/webp/krita_webp.desktop A +12 -0 plugins/impex/webp/krita_webp_export.json A +12 -0 plugins/impex/webp/krita_webp_import.json https://invent.kde.org/graphics/krita/commit/0d811d3464a8ba10f3c8dc705a302f030326a73d