Automatically optimize background images

What's Changed

• Background PNG and JPEG uploads are resized to at most 2048 pixels on the longest side and encoded as JPEG at quality 85, preserving aspect ratio without upscaling.
• Preserve EXIF orientation, flatten transparency onto black, and reject invalid or excessive pixel dimensions before replacing the current wallpaper.
• Use managed public-domain stb image libraries and permissively licensed metadata parsing without ImageMagick or native image-processing dependencies.

Release integrity

Native archives have matching platform-specific SPDX SBOM assets plus GitHub build-provenance and SBOM attestations. Installers and the built-in updater additionally verify a signed manifest and all packaged-file hashes.

Verification guide · Security policy