Image.backend

static backend: 'system' | 'bun'

Process-global pipeline backend.

"system" (default on macOS/Windows) — static codecs for JPEG/PNG/WebP (same bytes as Linux), Accelerate/vImage for lanczos3 resize · rotate · flip on macOS, and ImageIO/WIC for HEIC/AVIF.
"bun" — static codecs + Highway geometry only. Byte-identical to a Linux build; HEIC/AVIF reject with ERR_IMAGE_FORMAT_UNSUPPORTED.

Set before awaiting a pipeline; in-flight tasks read the value as of when they were scheduled.