When to use it
When you need a thumbnail and have no ideas — the preview drives CTR just as much as the title does. The role is art director. Result: 3 ready concepts (subject, emotion, text, contrast, hook) you can hand to a designer or build yourself.
The prompt (copy and paste)
You are an art director who makes high-CTR thumbnails.
VIDEO: "<PASTE THE TOPIC>". TITLE: "<PASTE THE TITLE>". NICHE/COMPETITORS: <briefly>.
Give me 3 different thumbnail concepts, and for each:
- The main subject in frame and its emotion (what reads in 0.5 seconds).
- The text on the thumbnail (≤ 3 words) and where it sits.
- Colour contrast and background (so it stands out in the feed).
- One hook detail that sparks curiosity.
At the end — which concept is strongest and why. Don't propose misleading visuals.
Filled-in example
Video: "I interviewed at FAANG — here's what they asked". Title: "FAANG interview: the real questions". Niche: tech careers.
What the AI should return: Concept 1 — a close-up face, emotion "nervous shock", text "Did I fail?", high-contrast red background, hook — a sheet of questions in hand. Concept 2 — a cracked big-tech logo, text "5 questions", cold blue. Concept 3 — an arrow from "junior" to "offer". Verdict: "#1 is strongest — face + emotion gives the highest CTR in the careers niche".
Variations
- Straight into a generator. "Rewrite concept #1 as a prompt for Midjourney/DALL·E" — and you get the image.
- An A/B pair. "Give me 2 thumbnails for the same video with different emotions, for a test."
- Brand book. Specify your brand colours and font — the concepts will fit the channel's style.
Pro tips
- Text on a thumbnail: 3 words max, set large. Small text is unreadable in the feed. Treat this as a hard rule.
- The classic mistake is a thumbnail promising something the video doesn't deliver: CTR spikes, retention collapses, the algorithm buries you. "Don't mislead" is in the prompt for a reason.
- The AI gives you the idea, but check the real thumbnail on a phone at feed size — that's where it actually competes.