thumbnail_skill

Overview

This skill generates Nano Banana Pro prompts for creating high-impact blog and YouTube thumbnail images. It is triggered when users mention Japanese thumbnail keywords such as サムネイル作成, サムネ, YouTube用画像, or ブログ画像. The output includes platform-aware prompt text and saving instructions so you can feed prompts directly into image-generation tools. It focuses on high-contrast, click‑driving designs and keeps required language and format rules in mind.

How this skill works

The skill inspects your title and theme, checks an internal idea backlog, and selects the appropriate platform size (OGP for blogs or 16:9 for YouTube). It asks for the thumbnail style (text-heavy, character, conceptual, or comparison) and character details when needed, applies anti-AI style options, and then fills a prompt template to produce a ready-to-use Nano Banana Pro prompt. Generated prompts and file paths are suggested for saving prompts and images, and the idea backlog is updated to track progress.

When to use it

• When you say サムネイル作成, サムネ, YouTube用画像, or ブログ画像
• When you have a title (preferably ≤20 characters) and a clear theme
• When you need platform-specific sizes (blog OGP or YouTube 16:9)
• When you want a prompt tailored for Nano Banana Pro image generation
• When you need guidance on character usage or anti-AI styling

Best practices

• Provide a concise title (20 characters or fewer recommended) and a short theme description
• Specify desired style early: text-centric, character, conceptual, or comparison
• For existing characters, attach a base image when using image-generation AI
• Choose high-contrast color schemes to increase click-through rate
• Use the anti-AI style options to reduce obvious synthetic artifacts

Example use cases

• Create a YouTube thumbnail prompt for a 1280x720 video about productivity tips
• Generate a blog OGP prompt (1200x630) for an article titled within 20 characters
• Produce a character-driven thumbnail prompt and include a base image note
• Make a comparison-style thumbnail prompt highlighting 'Before vs After'
• Convert an idea from the backlog into a finalized Nano Banana Pro prompt file