video-thumbnail-generator

# Video Thumbnail Generator Use this skill to create a high-clarity thumbnail or cover image from the actual video content. ## Non-Negotiables 1. Use the real video as visual evidence. - If the thumbnail shows a person, product, UI, frame, or scene from the video, extract or inspect real frames. - Never invent a generic software interface, fake product screen, or unrelated person. 2. Read style references before recommending styles. - Use `references/thumbnail-styles.md` and `references/thumbnail-style-recipes.md`. - Only offer style directions supported by those references or by the user's explicit instruction. 3. Keep text short and readable. - Usually 2-5 words. - Avoid thin type, low contrast, small labels, and clutter. ## Workflow 1. Confirm platform and aspect ratio if missing. - YouTube / Bilibili: usually 16:9. - Shorts / TikTok / Douyin: usually 9:16. - Xiaohongshu / WeChat Channels: usually 3:4. - Correct ambiguous ratio language gently, especially 4:3 vs 3:4. 2. Read project state, transcript, and available media context. 3. Inspect candidate frames: - expressive face - product or UI clearly visible - dramatic action moment - clean composition - strong lighting or clear subject separation 4. Classify the thumbnail job: - talking-head / opinion / tutorial - product / software / demo - cinematic / documentary / art - entertainment / challenge / reaction - education / business / concept 5. Propose concise title text options. 6. Offer 3-6 clearly different style directions. - Each option should name the composition, not only a channel/style label. - Exclude weak options. - Wait for user choice when the direction is not obvious. 7. Generate thumbnail options using selected real frames and the selected style. 8. Check mobile readability, subject fidelity, product/UI truthfulness, and visual contrast. 9. Present results and offer targeted adjustments. ## Prompt Shape ```text [Platform] thumbnail, [aspect ratio / dimensions], [style name]. COMPOSITION: [subject position, scale, background, graphic balance] REAL REFERENCE: [describe selected frame zone by zone] TEXT: "[short title]" in [high-contrast style] STYLE: [one-line style recipe from references] CONSTRAINTS: readable at mobile size, no fake UI, no watermark, no play button. ``` ## References - `references/thumbnail-styles.md`: style library from real thumbnail analysis. - `references/thumbnail-style-recipes.md`: quick style recipes and prompt patterns. - `references/field-testing-notes.md`: known failure modes.