Handles extraction of the embedded rimage backend executable to a per-user cache directory with SHA-256 integrity verification and version probing (`--version`). The design is robust: it uses a temp file with hash check before replacing the target, handles concurrent instances gracefully via `File.Replace`, and allows development builds to locate the backend in the repository's `res/` folder instead of embedding. This pattern is reusable for any application that needs to ship and verify an external native tool.

Builds the rimage command-line arguments from the processing options, carefully handling quality/lossless mode logic, quantization/dithering coupling, resize argument normalization, and thread resolution. It uses a file list approach to keep command lines short and writes metadata for reliable output path tracking. The quoting logic in PathUtil.QuoteArgument correctly handles the tricky `CommandLineToArgvW` rules (trailing backslashes, embedded quotes). This module encapsulates all knowledge of rimage's CLI surface, making the application resilient to future backend changes.

Performs thorough pre-job validation: checks file existence, quality ranges, suffix validity (Windows reserved names), mutual exclusion of backup and suffix, output directory existence, thread count bounds, resize argument syntax (normalizes `720x_` to `720w`, etc.), and collision detection for duplicate outputs and outputs that would overwrite other inputs. The `PredictedOutputPath` method and `SafeToDelete` guard are critical safety components. The validation logic is well-isolated and tested, making it reusable in other CLI-wrapping utilities.