Feature

Thumbnail text that adds curiosity — in five words or less

The words on a thumbnail have one job: make someone want to know more. Ask the agent for text ideas and get 5–10 short options, each with a note on why it works.

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Text rules the agent follows

2–5 words, about 25 characters at most — readable on a phone at a glance.
One idea per thumbnail: a hook, a promise, a question, a bold claim or a number.
Works with the title instead of repeating it. Title and thumbnail should tell a story together.
Plain, punchy words, no hashtags and no punctuation clutter. Capitals for one word of emphasis at most.
Your language — the agent writes in the language you use.

Examples of strong thumbnail text

“IT’S GONE”

Creates a question in two words — what’s gone, and why?

“$12 vs $1,200”

A number contrast promises a clear comparison.

“Don’t buy this”

A warning taps into fear of making a mistake.

“Day 100”

Signals a payoff after a long challenge.

“I was wrong”

Personal admission builds curiosity and trust.

No text at all

Sometimes the image says it all — and it gives you an A/B test variant.

From text to finished thumbnail

Pick the option you like and ask the agent to design it. The text is quoted exactly in the image prompt so it renders as written. For more on writing it, read thumbnail text tips.

Frequently asked questions

Does ThumbSpark write YouTube titles?

No — it focuses on the short text on the thumbnail itself. That text should complement your title, not duplicate it.

Can AI images render text correctly?

Modern image models render short text well, especially when it’s quoted exactly. Keeping it to a few words also makes it much more reliable.

Make your next thumbnail in minutes

Tell the AI agent what your video is about — it proposes a thumbnail, you approve it, and you can tweak it by asking.

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