# Markdown Image Grants

## Purpose

This module lets the Markdown image gallery display images that an assistant
explicitly referenced from OpenCode's temporary directory when the UI is on a
different machine.

## Contract

- Chat Markdown rendering is independent: assistant image syntax renders as an
  icon and filename, while the gallery only reads finalized Markdown to collect
  image candidates.
- `POST /api/openchamber/sessions/:sessionId/markdown-image-grants` prepares up to 12
  local images in one message-level request. The server fetches the assistant
  message once and verifies every exact image source before reading files.
- Relative and workspace-contained absolute paths resolve against the active
  directory. Other absolute paths are accepted only inside
  `os.tmpdir()/opencode` after `realpath` resolution.
- PNG, JPEG, GIF, and WebP files are signature-checked and limited to 10 MiB.
- Prepare requests inspect only file metadata and signatures. Workspace images
  reuse the existing authenticated `/api/fs/raw` asset route directly. Images
  under `os.tmpdir()/opencode` receive the existing path-bound `raw`
  `outsideFileGrant`; this module does not add another asset lifetime, copy, or
  storage layer. Missing files return per-source results so the gallery can
  remove only those items.

The routes are OpenChamber-owned and must be registered before the generic
OpenCode proxy. Web, Electron, hosted mobile, and Capacitor use the shared
server implementation. VS Code returns an explicit unsupported response.