For the complete documentation index, see llms.txt. Markdown versions of all pages are available by appending .md to any URL (e.g. /max/get-started.md).

Python function

hash_image

`hash_image()`

max.support.image.hash_image(image, size_tier=None)

source

Compute the hash of an image.

Two input modes are supported:

Raw encoded bytes (preferred for prefix-cache / routing keys): pass the raw encoded image container bytes (the JPEG/PNG/WebP bytes as received by the router, before any decode or resize) as image, together with a size_tier capturing the resolution class the image is processed at. Because it never touches decoded float pixels, the result is byte-identical across torch/numpy/BLAS versions and CPU-vs-GPU, so it is safe as a key that a separate encoder must reproduce. This mirrors that encoder’s content_key: xxh3_64(bytes ++ size_tier) with size_tier appended as a little-endian unsigned 64-bit integer.
Decoded pixels (legacy): pass a numpy pixel array as image and omit size_tier. Supports any dtype (float32, uint16 for bfloat16 bits, etc.) and ensures a C-contiguous layout before hashing. The digest depends on the post-resize float pixels, so it is not reproducible across torch/BLAS/device; prefer the raw-bytes mode where the encoded bytes are available.

In both modes the unsigned 64-bit digest is reinterpreted as a signed 64-bit int for numpy int64 token-hash compatibility.

Parameters:

image (ndarray[tuple[Any, ...], dtype[Any]] | bytes) – Either the raw encoded image bytes or a decoded numpy pixel array.
size_tier (int | None) – The resolution size class folded into the key, so identical bytes processed at different resolutions key distinctly. Required when image is bytes; must be omitted for a pixel array.

Returns:

The signed 64-bit image hash.

Raises:

ValueError – If image is bytes and size_tier is not provided, or if image is a pixel array and size_tier is provided (the tier is only folded into the raw-bytes key, so passing it with a pixel array is a silent no-op we reject rather than swallow).
OverflowError – If size_tier is negative or does not fit in an unsigned 64-bit integer, since the key appends it as a little-endian u64.

Return type:

int

hash_image()​

`hash_image()`