Upload images and files to GitHub from command line

This skill uses gh-image, an extension for the GitHub CLI, to upload a local image and obtain a hosted user-attachments reference. It then embeds the returned Markdown in a pull request, issue, comment, or README. Typical requests include attaching screenshots to a pull request, placing images in an issue, or showing test results and before-and-after evidence from the terminal.

The extension follows GitHub's internal browser upload flow rather than a public image-upload API. It prints one Markdown line per image to standard output. The surrounding skill captures that output and edits the destination; the extension itself does not update the pull request or issue. The extension is authored by drogers0 and distributed under the MIT license.

Use the workflow for an authorized image transfer to a verified GitHub repository. Before uploading, confirm the intended repository, the image's privacy requirements, and the explicit transfer scope. An unguessable attachment URL or private repository alone does not prove confidentiality. Check access with the intended audience, and choose another approved sharing method when confidentiality cannot be established.

The upload endpoint requires a GitHub user_session cookie instead of the normal gh authentication token. Credential resolution considers an explicit token flag, GH_SESSION_TOKEN, and then a logged-in browser's cookie store. The instructions prohibit passing session values through the token flag and require authorization before accessing browser cookies. Do not inspect unrelated browser profiles.

A session cookie grants broad account access rather than the narrower scope of a personal access token. Treat it as a password. CI use calls for a dedicated account and a configured GH_SESSION_TOKEN. Repository write access is required, and organizations enforcing SAML SSO also need the session authorized for the organization.

The input is a local image path and, where needed, an explicit repository. Resolve file globs to absolute paths and quote paths containing spaces or Unicode. An upload example is:

gh image "/abs/path/screenshot.png" --repo <owner>/<repo>

Capture the Markdown output as the embeddable reference. For an existing pull request description, preserve the current body and append screenshots under the relevant heading. Updating an issue or adding a comment uses the corresponding gh command. Pass multiline content through a body file or standard input so quoting and special characters do not corrupt it.

Preparation checks that gh is installed and authenticated and that the extension is available; review or pin its implementation before installation. After editing, read the destination body again and confirm the attachment reference is present. Internal endpoints and access behavior can change, so destination-reference verification and audience verification serve different purposes.

For display sizing, the workflow supports an HTML image tag in the destination content. Windows with Chrome 127 or later has a cookie-reading library limitation; use another browser or the configured session environment variable instead.