Generate outputs for images and pipelines

You are given m input images and n processing pipelines.

• Each pipeline is an ordered list of k operations (e.g., resize, rotate, crop, blur, color transform).
• Applying a pipeline to an image produces a new output image.

Task

Write a function/program that produces m × n output images by applying every pipeline to every input image.

Requirements

• Each output should be associated with (image_id, pipeline_id).
• The pipeline operations must be applied in order.
• Assume images are stored as file paths; pipelines are provided as callable operations.
• Your implementation should be structured so it can be parallelized easily (e.g., avoid unnecessary repeated work such as reading the same image multiple times).

Input/Output (one reasonable interface)

• Input:
• image_paths: List[str] (size m)
• pipelines: List[List[Callable[[Image], Image]]] (size n, each of length k)
• output_dir: str
• Output:
• Write m*n images to output_dir with deterministic names like img{idx}_pipe{j}.png, or return a list of output file paths.

Constraints (assume)

• m, n can be large enough that runtime and I/O efficiency matter.
• Operations may be CPU-bound; image decoding/encoding is I/O-bound.

Follow-up discussion (no need to implement)

• How would you scale this for large m and n?
• What parallelization strategy would you choose and why?