Generate thumbnail concepts and ideas for YouTube, TikTok, and other video platforms. Creates detailed visual briefs with composition, text, colors, and emotion suggestions.
SkillScore78Maintained
Automatic
◆Marketing & Content pack
Last verified 8/24/2026
What it changes
Passed 18 of 23 test cases with the skill, and 12 of 23 without it.
Without skill52%
With skill78%
Checks it passed that the model alone missed
Limits overlay text to 3-4 words maximum.
Evaluates performance over the first 48 hours.
Positions the result or outcome with short text on one side.
and 7 more in the full report
7 fixed11 passed either way4 still failing1 broke
Pass-rate lift
+26 pp
Tokens
+86%
Agent turns
0%
Response time
-21%
Model gemini-3.6-flashMeasured 8/24/2026v118 of 23 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 7 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 7
Prompt
When including my face in YouTube thumbnails for high CTR, what percentage of the thumbnail frame should my face occupy, and what key rule applies to eye placement?
What was checked, without and with the skill
Checked
Without skill
With skill
Recommends that the face occupies 30% to 50% of the thumbnail frame.
Missed
Passed
Specifies maintaining direct eye contact with the camera with visible expressive eyes.
Missed
Passed
case-05 · gemini-3.6-flash · 8/24/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md287 linessingle file
Thumbnail Concept Generator
Create click-worthy thumbnail concepts that maximize CTR.
Thumbnail Psychology
📊 THUMBNAIL IMPACT:
- 90% of top-performing videos have custom thumbnails
- Thumbnails are responsible for ~50% of a video's click-through rate
- Viewers decide in <2 seconds whether to click
KEY PRINCIPLE: Thumbnail must work at SMALL sizes (mobile, sidebar)
Thumbnail Elements
1. Faces & Emotions
EMOTION SCALE (from most to least effective):
1. 😱 Shock/Surprise - Wide eyes, open mouth
2. 🤔 Curiosity - Raised eyebrow, intrigued look
3. 😄 Joy/Excitement - Genuine smile, energy
4. 😤 Frustration/Anger - Visible emotion
5. 🤯 Mind-blown - Exaggerated reaction
6. 😢 Sadness - For emotional content
FACE RULES:
- Eyes should be visible and expressive
- Face takes up 30-50% of thumbnail
- Direct eye contact with camera
- Avoid sunglasses/obstructions
2. Text Overlay
TEXT RULES:
- Maximum 3-4 words
- Large, bold, readable at small size
- Contrasting colors (white on dark, dark on light)