Slash Command

Thumbnail

Generate YouTube-style thumbnails with text overlays, faces, and

Type: Slash Command
Repository: jeremylongshore/tons-of-skills-marketplace
GitHub stars: 2.8k
License: MIT
Repo last updated: Sep 27, 2026
Source file: plugins/packages/creator-studio-pack/plugins/video-production/thumbnail-designer/commands/thumbnail.md

What Thumbnail is

Thumbnail is a slash command published in the jeremylongshore/tons-of-skills-marketplace repository on GitHub, which has about 2.8k stars. The repository describes itself as: “Model-agnostic agent-skills platform with a harness-free canonical layer, verified adapters, and the ccpi package manager. Explore at tonsofskills.com.”

A slash command is a reusable prompt saved as a markdown file and run by typing its name after a slash. In Claude Code, custom commands have been merged into skills: a file in .claude/commands/ and a skill folder in .claude/skills/ both create the same kind of command, and existing command files keep working.

Thumbnail gives you a repeatable way to run the same instructions without retyping them, optionally with arguments.

How to install Thumbnail

Claude Code

Download thumbnail.md from the repository.
Save it to ~/.claude/commands/ (all projects) or .claude/commands/ (one project). As a skill, you can instead save it as ~/.claude/skills/<name>/SKILL.md.
Run it by typing / followed by its name.

Claude Cowork

Turn the command into a skill: create a folder with the file saved as SKILL.md and zip it.
In Customize → Skills, click +, then upload the ZIP.
Run it from any task with / and the skill name.

New to extending Cowork? Our plugins guide and Customize guide explain how skills, plugins, and connectors fit together.

Inside the source file

An excerpt from plugins/packages/creator-studio-pack/plugins/video-production/thumbnail-designer/commands/thumbnail.md, shared under the repository's MIT license. Read the full file on GitHub.

Generate high-CTR YouTube thumbnails with AI-assisted design and proven formulas.

Usage

/thumbnail "[video title]"                    # Generate from title
/thumbnail "[title]" --style mr-beast         # Use specific style
/thumbnail "[title]" --face screenshot.png    # Use face from image
/thumbnail analyze [existing-thumbnail.jpg]   # Analyze existing thumbnail
/thumbnail batch [video-list.txt]             # Generate multiple

Purpose

Create thumbnails that:

Stop the scroll - Eye-catching in feed
Communicate value - Clear what video is about
Optimize CTR - A/B test multiple versions
Match brand - Consistent style across channel

Thumbnail Formulas

Formula 1: Mr Beast Style

Elements:
- Large expressive face (40% of thumbnail)
- 3-5 words in huge text
- High contrast colors (red, yellow, blue)
- Shocked/excited expression
- Minimal background, maximum focus

Best For: Entertainment, challenges, reactions
Example: "I SPENT $100,000 ON THIS?!"
CTR Benchmark: 12-18%

Formula 2: Ali Abdaal Style

Elements:
- Clean minimalist design
- Professional headshot
- Bold sans-serif text (2-4 words)
- Subtle background (blurred or gradient)
- Icons or simple graphics

Best For: Education, productivity, tutorials
Example: "How I Read 100 Books"
CTR Benchmark: 8-12%

Formula 3: Tech Review Style

Elements:
- Product photo (professional)
- "VS" or comparison layout
- Verdict indicator (✓/✗ or rating)
- Clean text with stats/numbers
- Tech aesthetic (dark mode, neon)

Best For: Reviews, comparisons, tech content
Example: "MacBook M3 vs M2: Worth It?"
CTR Benchmark: 10-14%

Formula 4: Tutorial Style

Elements:
- Before/After split
- Large text describing outcome
- Arrows showing transformation
- Professional but accessible
- Step number or duration badge

Best For: How-to, tutorials, courses
Example: "10x Faster API in 15 Minutes"
CTR Benchmark: 7-11%

Formula 5: Vlog Style

Elements:
- Candid action shot
- Location or context visible
- Personal/relatable moment
- Casual text overlay
- Warm, authentic colors

Best For: Behind-the-scenes, vlogs, personal
Example: "Building My Startup (Day 47)"
CTR Benchmark: 6-10%

Implementation

When user runs /thumbnail "How I Made My API 10x Faster":

Step 1: Analyze Title

📊 TITLE ANALYSIS

Title: "How I Made My API 10x Faster"
Category: Technical tutorial
Keywords: API, performance, speed
Hook: "10x Faster" (specific result)

Recommended Style: Tutorial (Formula 4)
Alternative: Tech Review (Formula 3)

Step 2: Generate Design Concepts

🎨 GENERATING 3 CONCEPTS

Concept A: "Tutorial Style" (Recommended)
├─ Layout: Before/After split screen
├─ Left: "SLOW API" with 2000ms badge
├─ Right: "FAST API" with 180ms badge
├─ Center: Large "10x" with arrow
├─ Bottom: "In 1 Hour" time badge
├─ Colors: Red → Green gradient
└─ Predicted CTR: 9.5%

Concept B: "Tech Style"
├─ Layout: Code editor screenshot
├─ Text: "10x FASTER API" (huge, top)
├─ Subtext: "Redis Tutorial"
├─ Performance graph overlay
├─ Colors: Dark mode + neon green
└─ Predicted CTR: 8.2%
…

Step 3: Generate Thumbnail

✨ GENERATING THUMBNAIL

Concept A (Tutorial Style)
[▓▓▓▓▓▓▓▓▓▓] 100%

Created:
- thumbnails/api-10x-faster-A.png (1280x720)
- thumbnails/api-10x-faster-A-preview.jpg (480x270)

Design Details:
├─ Font: Inter Bold (96pt main, 48pt subtext)
├─ Colors: #EF4444 → #10B981 gradient
├─ Elements: 2 screenshots, 1 arrow, 2 badges
├─ Text Hierarchy: Clear, readable at small size
└─ File Size: 186 KB (optimized for upload)

Mobile Preview:
[Shows 100x100px preview - text still readable? ✓]
…

Step 4: A/B Test Recommendations

📈 A/B TEST STRATEGY

Test These Variants:
1. With vs without face
2. "10x Faster" vs "10x Speed Boost"
3. Dark mode vs light mode background
4. Graph overlay vs clean design

Run 1,000 impressions each
Winner typically clear after 24 hours
Expected CTR improvement: 20-40%

Before you install

Read the whole file first. Skills, commands, and subagents are instructions Claude will follow, so make sure they match what you want.
Check which tools, scripts, or MCP servers it uses. Local servers and scripts run with your permissions.
Try it in a test project or a copy of your files before pointing it at real work.
Pin the version you tested, and review changes before updating.
Watch for instructions that fetch web content or run shell commands; those are where prompt injection risks start. See our prompt injection guide.

FAQ

What is Thumbnail?

Thumbnail is a slash command for Claude Code and Claude Cowork from the jeremylongshore/tons-of-skills-marketplace repository on GitHub. Generate YouTube-style thumbnails with text overlays, faces, and

How do I install Thumbnail in Claude Code?

Download thumbnail.md from the repository. Save it to ~/.claude/commands/ (all projects) or .claude/commands/ (one project). As a skill, you can instead save it as ~/.claude/skills/<name>/SKILL.md. Run it by typing / followed by its name.

Can I use Thumbnail in Claude Cowork?

Turn the command into a skill: create a folder with the file saved as SKILL.md and zip it. In Customize → Skills, click +, then upload the ZIP. Run it from any task with / and the skill name.

Is Thumbnail safe to install?

It is a third-party community resource, not reviewed by Anthropic or this site. Read the source file first, check which tools and connectors it uses, and install only from sources you trust.

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Listing data comes from the public GitHub repository and was last checked in September 2026. Excerpts are © their authors and shared under MIT. This directory is independent and not affiliated with Anthropic or the resource's authors.