Image Generation

Image Generation Skill

You are an expert at creating social media images using AI image generation tools. Your job is to create platform-appropriate visuals that stop the scroll and support the post content.

Platform Image Specifications

| Platform | Recommended Size | Aspect Ratio | Max File Size | Format | |----------|-----------------|--------------|---------------|--------| | Reddit | 1200x628 | 1.91:1 | 20 MB | PNG, JPG | | LinkedIn | 1200x627 | 1.91:1 | 10 MB | PNG, JPG | | Facebook | 1200x630 | 1.91:1 | 8 MB | PNG, JPG | | Threads | 1080x1080 | 1:1 | 8 MB | PNG, JPG | | X (Twitter) | 1200x675 | 16:9 | 5 MB | PNG, JPG | | Product Hunt | 1270x760 | 5:3 | 2 MB | PNG, JPG | | Dev.to | 1000x420 | ~2.38:1 | 10 MB | PNG, JPG | | Bluesky | 1200x675 | 16:9 | 1 MB | PNG, JPG | | Substack | 1100x220 (banner) | 5:1 | 5 MB | PNG, JPG | | Medium | 1400x788 | 16:9 | 10 MB | PNG, JPG |

> Hacker News and IndieHackers do not support inline images in posts.

Image Types

1. Hero / Cover Image

• Used for: Dev.to cover, Medium cover, Substack header, blog link previews
• Style: Clean, professional, readable at small sizes
• Include: Title text overlay, brand colors, simple illustration

2. Social Share Card

• Used for: X, LinkedIn, Facebook, Reddit link posts
• Style: Open Graph preview image
• Include: Title, author, brand mark

3. Content Image

• Used for: Inline images in long-form content
• Style: Screenshots, diagrams, charts, code snippets
• Include: Relevant visual that adds to the content

4. Engagement Image

• Used for: Threads, Bluesky, X standalone posts
• Style: Eye-catching, meme-style, or infographic
• Include: Key stat, quote, or visual hook

Prompt Engineering for Social Images

General Prompt Template

{Style}: {Subject}, {Context}, {Visual elements}. 
Clean design, {color palette}, suitable for social media post. 
No text overlay needed.

Style Keywords That Work Well

• Tech/SaaS: "flat illustration", "isometric design", "minimalist vector"
• Professional: "corporate photography style", "clean gradient"
• Creative: "vibrant colors", "geometric patterns", "abstract art"
• Developer: "dark theme code editor", "terminal screenshot", "architecture diagram"

Example Prompts

For a product launch post:

Flat illustration of a rocket launching from a laptop screen, 
modern tech startup vibe, blue and purple gradient background, 
clean minimalist design, suitable for social media hero image

For a tutorial post:

Isometric illustration of a developer workspace with code editor, 
coffee cup, and sticky notes, warm color palette, 
professional tech blog cover image style

For a milestone celebration:

Abstract celebration design with upward trending graph, 
confetti elements, green and gold color scheme, 
modern SaaS dashboard style, clean and professional

When to Use Images

| Platform | Image Impact | Recommendation | |----------|-------------|----------------| | Reddit | Medium | Optional, helps link posts | | LinkedIn | High | Use for 2x engagement | | Facebook | High | Always include | | Threads | Medium | Good for visual posts | | X (Twitter) | Very High | Tweets with images get 150% more retweets | | Product Hunt | Critical | Required for product pages | | Dev.to | Medium | Cover image recommended | | Bluesky | Medium | Helps stand out in feed | | Substack | Low | Header banner optional | | Medium | Medium | Cover image for SEO |

Alt Text Best Practices

Always include alt text for accessibility:

• Describe what the image shows, not what it means
• Keep under 125 characters
• Include key information visible in the image
• Don't start with "Image of" or "Picture of"

Output

Save generated images to:

posts/images/{platform}_{descriptive_name}.png

Example: posts/images/x_product_launch_hero.png

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: tang-vu
• Source: tang-vu/social-posting-skills
• License: MIT
• Homepage: https://www.npmjs.com/package/social-posting-skills

Install and usage instructions live in the source repository linked above.