image-resizer

Skill Overview

• Adjust images to specified pixel dimensions (e.g., 800×600)
• Scale images by ratio (e.g., 50% reduction, 200% enlargement)
• Limit maximum size (maintain aspect ratio, e.g., maximum 1920×1080)
• Crop to specified aspect ratio (e.g., 16:9, 4:3)
• Compress images to specified size (e.g., compress to ≤500KB)
• Batch process multiple images

Script Usage Instructions

Install Dependencies

cd scripts
npm install

Basic Usage

node resize_image.js <input image> [options]

Option Description

--width

-w

-w 800

--height

-h

-h 600

--scale

-s

-s 0.5

--max-width

--max-width 1920

--max-height

--max-height 1080

--quality

-q

-q 80

--size

-S

-S 500

--format

-f

-f webp

--output

-o

-o output.png

--aspect-ratio

-a

-a 16:9

--fit

--fit cover

Fit Mode Description

cover

contain

fill

inside

outside

Usage Examples

Example 1: Adjust to specified dimensions

node resize_image.js input.png -w 800 -h 600 -o output.png

Example 2: Scale by ratio

node resize_image.js input.png -s 0.5 -o output.png

Example 3: Compress to specified size

node resize_image.js input.png -S 500 -o output.jpg

Example 4: Crop to specified aspect ratio

node resize_image.js input.png -a 16:9 -o output.png

Example 5: Maximum size limit (maintain aspect ratio)

node resize_image.png input.png --max-width 1920 --max-height 1080 -o output.png

Example 6: Convert to WebP and compress

node resize_image.js input.png -f webp -q 80 -o output.webp

Typical Workflows

Workflow 1: Generate website thumbnails

1. Read original image
2. Limit maximum width to 1200px, maintain aspect ratio
3. Compress to ≤300KB
4. Output as JPEG format

node resize_image.js photo.jpg --max-width 1200 -S 300 -f jpg -o thumbnail.jpg

Workflow 2: Generate social media images

1. Read original image
2. Adjust to 1080×1080 square
3. Compress to ≤500KB

node resize_image.js input.png -w 1080 -h 1080 -S 500 -o instagram.png

Workflow 3: Generate 16:9 landscape images

1. Read original image
2. Crop to 16:9 ratio (center-aligned)
3. Compress to ≤200KB

node resize_image.js input.png -a 16:9 -S 200 -o 16_9.jpg

Skill File Structure

image-resizer/
├── SKILL.md                    # Skill main file
└── scripts/
    ├── resize_image.js         # Image processing script
    └── package.json            # Dependency configuration

Dependency Description

• sharp: Image processing library that supports conversion, cropping, and compression of formats such as PNG, JPEG, WebP, etc.