Built-in image_gen generates an inline image, but does not return or expose a usable saved file path.

Issue: Built-in image_gen generates an inline image, but does not return or expose a usable saved file path.

Environment:
Windows
Codex CLI: codex-cli 0.130.0-alpha.5
Date: 2026-06-18

Steps:

1. Use the built-in image_gen tool in a Codex desktop thread.
2. Generate a simple image with no input-image dependencies.
3. The image appears inline in the conversation.
4. Check C:\Users\79447\.codex\generated_images and common cache/temp directories.

Actual:
The image is visible inline, but no new PNG/JPG appears in .codex\generated_images.
The tool response exposes no saved_path/file_path/artifact_path.
From the agent side this is effectively path = null.

Expected:
image_gen should return a usable saved_path, or save consistently to .codex\generated_images, or expose an artifact handle that Codex can copy into the workspace.

Impact:
Generated images cannot be copied into the project, versioned, post-processed, or referenced reliably by path.