# Trello Set Thumbnail > This skill should be used when the user asks to "set thumbnails for Trello cards", "add thumbnail frontmatter", "populate thumbnail field", or wants to add a `thumbnail` frontmatter field from the first image found in imported Trello card Markdown files. Use when this capability is needed. - Skill: `tomevault-io/trello-set-thumbnail` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/trello-set-thumbnail` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/trello-set-thumbnail/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/trello-set-thumbnail --- # Trello Set Thumbnail Skill Add or update a `thumbnail` frontmatter field in imported Trello card notes, using the first image found in each file. ## When to Use - After running `trello-import` (and optionally `trello-media-download`) - When card notes should have a `thumbnail` field pointing to their first image ## Bundled Script The thumbnail setter script is bundled at `scripts/set_thumbnail_frontmatter.py`. Run from the repository root: ```bash python3 .claude/skills/trello-set-thumbnail/scripts/set_thumbnail_frontmatter.py ``` ## Options | Flag | Description | |------|-------------| | `--root PATH` | Directory to scan (default: `TRELLO_IMPORT`) | | `--pattern GLOB` | File pattern under root (default: `**/index.md`) | | `--field NAME` | Frontmatter field name to set (default: `thumbnail`) | ## Behavior - Scan each Markdown file for the first `![alt](target)` image link in the body (below frontmatter) - Add or update the `thumbnail` field in YAML frontmatter with that image target - Remove any legacy `thumnbnail` (typo) field if present - Skip files without frontmatter or without images ## Recommended Workflow 1. Run `trello-import` to generate card notes. 2. Run `trello-media-download` to localize images. 3. Run `trello-set-thumbnail` to populate frontmatter thumbnails. --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/erich3000) — claim your Tome and manage your conversions.