GitHub Upload Image to PR

[!IMPORTANT] This skill now prefers GitHub CLI's native --attach flag (gh 2.99.0+). When your gh is new enough, it runs gh pr edit --attach ./screenshot.png (or gh pr comment --attach) and is done — no browser automation, no MCP server, no flakiness. On older gh it prompts you to upgrade and falls back to the browser route so the work still gets done. See the v2.99.0 release notes and GitHub's docs.

An AI agent skill that uploads local images to a GitHub PR and embeds them in the description or comments — automatically, just by asking.

日本語版はこちら

Installation

gh skill install tonkotsuboy/github-upload-image-to-pr github-upload-image-to-pr

or

npx skills add tonkotsuboy/github-upload-image-to-pr

Usage

Trigger the skill with phrases like:

• "Attach this screenshot to the PR"
• "Add images to the PR description"
• "Upload test results to the PR"
• "Put this screenshot in the PR"
• "Embed before/after images in the PR"

How It Works

The skill picks one of two paths based on your gh version.

Path A — gh --attach (preferred, gh 2.99.0+)

GitHub CLI 2.99.0 added a repeatable --attach flag to gh pr create / pr edit / pr comment (and the matching gh issue commands), so uploading is a single command:

gh pr edit 23 --attach './screenshot.png#Login error state'
gh pr comment 23 --attach ./before.png --attach ./after.png

Without --body, the existing description is kept and the attachment appended. If the body references a local path such as ![before](./before.png), that reference is rewritten in place — which is how you get Before/After tables and other layouts from one command.

Requires push access to the repository, and works on GitHub.com and GitHub Enterprise Cloud (not Enterprise Server).

Path B — browser upload (fallback)

GitHub does not provide a public REST API endpoint for uploading image attachments, so before --attach existed the only route was to drive a browser the way a human would:

1. Open the PR page in a browser via Chrome DevTools MCP or Playwright MCP
2. Locate the comment textarea at the bottom of the PR conversation
3. Upload the image file using the file input attached to the textarea — this triggers GitHub's internal upload pipeline and generates a persistent https://github.com/user-attachments/assets/... URL
4. Extract the URL from the textarea value before submitting anything
5. Clear the textarea (the image URL remains valid even without posting the comment)
6. Update the PR description via gh pr edit, embedding the image as markdown

This works because GitHub's image hosting is separate from comment submission — images persist the moment they're uploaded, whether or not the comment is ever posted. The skill uses this path when gh is older than 2.99.0, when the host is Enterprise Server, or when you lack push access.

Requirements

• An AI agent that supports skills (e.g., Claude Code)
• GitHub CLI (gh) — 2.99.0 or newer for Path A; required in both paths
• Only for Path B (older gh), one of the following browser automation tools:
  • Chrome DevTools MCP (recommended — connects to your existing browser, login state preserved)
  • Playwright MCP (connects to an existing browser instance)

License

MIT

Copyright 2026 tonkotsuboy