banner-creator

Banner Creator Skill

Create professional banners through AI image generation with an iterative design process.

Prerequisites

Required API Keys (set in environment):

• GEMINI_API_KEY - Get from Google AI Studio

Required Skills:

• nanobanana - AI image generation (Gemini 3 Pro Image)

File Output Location

All generated files should be saved to the .skill-archive directory:

.skill-archive/banner-creator/<yyyy-mm-dd-summaryname>/

Example:

.skill-archive/banner-creator/2026-01-19-opc-banner/
  banner-01.png
  banner-02.png
  ...
  banner-03-cropped.png
  preview.html

Workflow

Step 1: Discovery & Requirements

Before generating, gather requirements from user:

Ask about:

1. Purpose - Where will the banner be used?

   • GitHub README
   • Twitter/X header
   • LinkedIn banner
   • Website hero
   • YouTube channel art

2. Target ratio/size - See references/formats.md:

   • 2:1 (1280x640) - GitHub README
   • 3:1 (1500x500) - Twitter header
   • 16:9 (1920x1080) - Website hero

3. Style preference:

   • Match existing logo/brand?
   • Pixel art / 8-bit retro
   • Minimalist / flat design
   • Gradient / modern
   • Illustrated / artistic

4. Content elements:

   • Brand name / project name?
   • Tagline / slogan?
   • Logo character to include?

5. Color preferences:

   • Existing brand colors?
   • Let AI decide?

Wait for user confirmation before proceeding!

Step 2: Generate Banner Variations

Generate 20 banner variations using the nanobanana skill:

# Generate single banner
python3 <

Guidelines:

• Generate at 21:9 ratio (widest available), crop later to target
• Use batch_generate.py for multiple variations (includes auto-delay)
• Use sequential naming: banner-01.png, banner-02.png, etc.

Image Editing (for incorporating existing logo):

Step 3: Create HTML Preview

Copy the preview template and open in browser:

Then open in default browser:

IMPORTANT: Update the HTML to include the correct number of banners generated.

Step 4: Iterate with User

Ask user which banners they prefer:

• "Which banners do you like? (e.g., #3, #7, #15)"
• "What do you like about them?"
• "Any changes you'd want?"

Based on feedback:

1. Generate 10-20 more variations of favorite styles
2. Use naming: banner-{original}-v{n}.png (e.g., banner-03-v1.png)
3. Update HTML preview
4. Repeat until user selects final banner

Step 5: Crop to Target Ratio

Once user approves a banner, crop to target size:

Common targets:

• GitHub README: --ratio 2:1 --width 1280 → 1280x640
• Twitter header: --ratio 3:1 --width 1500 → 1500x500
• Website hero: --ratio 16:9 --width 1920 → 1920x1080

Step 6: Deliver Final Assets

Present final deliverables:

Quick Reference

Common Prompt Patterns

With Text:

With Character:

Abstract/Gradient:

Scene-based:

Supported Aspect Ratios

Generate at widest ratio, then crop:

• 21:9 - Ultra-wide (recommended for generation)
• 16:9 - Wide
• 3:2 - Standard wide

References

• references/formats.md - Common banner sizes by platform
• examples/opc-banner-creation.md - Full example conversation