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README.md

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-# youtube-thumbnail-tests
+# YouTube Thumbnail Experiments
 
-YouTube thumbnail concept tests with Raphael AI
+A checklist for testing thumbnail concepts with [Raphael AI](https://raphael.app).
+
+## 1. One subject, big
+
+Thumbnails are viewed tiny. Prompt for a single bold subject filling 60% of the frame.
+
+## 2. High contrast
+
+Use complementary colors: `orange subject on deep blue background`.
+
+## 3. Emotion
+
+For faces, specify the emotion strongly: `shocked expression, wide eyes`.
+
+## 4. A/B test
+
+Make two concepts and use your platform's test feature to compare click-through.
+
+## Tips
+
+- Add text in an editor, max four words.
+- Check the thumbnail at 160 px width before uploading.
+- Avoid misleading imagery; it hurts retention.
+
+## About the tool
+
+[Raphael AI](https://raphael.app) is a free browser-based text-to-image generator; no account is needed to try it: https://raphael.app
+
+License: CC BY 4.0 for the notes in this repository.