Add skill: drogers0/github-image-upload

[drogers0]

Adds the github-image-upload Agent Skill to Community Skills → Development and Testing.

GitHub has no public API for the attachment uploads its web UI accepts via drag-and-drop, so agents cannot attach a screenshot or a log file to a PR or issue. This skill drives the gh-image gh CLI extension to upload a local file and return a canonical user-attachments URL, then embeds it in the PR/issue/comment.

• Handles any GitHub-supported attachment: images render inline, videos as players, and other files (PDF, zip, log) as download links.
• Uploads on private repos stay private, URLs inherit repository visibility.
• SKILL.md: https://github.com/drogers0/gh-image/tree/main/skills/github-image-upload
• MIT licensed, public repo, actively maintained (latest release v1.1.0).
• Adoption: 140 stars, 14 forks, 23,000+ release downloads across 9 releases.
• Agent-agnostic: Claude Code, Codex, Cursor, Gemini CLI.
• Install the underlying extension: gh extension install drogers0/gh-image

Previously opened as #716, which was closed without comment during the July 10 backlog cleanup. Resubmitting with an expanded scope (all attachment types, not just images) and the entry pointing directly at the SKILL.md — happy to adjust if there is anything specific you would like changed.