AgentSkillsCN

image_resize

在保持宽高比的前提下，对图像进行缩放、裁剪和旋转操作。当用户需要按宽度或高度调整图像尺寸、裁剪至特定坐标，或对图像进行旋转时，可使用此技能。

SKILL.md
--- frontmatter
name: image_resize
description: Resize, crop, and rotate images with aspect ratio preservation. Use this skill when the user needs to resize images by width/height, crop to specific coordinates, or rotate images.

Image Resize

This skill provides utilities to resize images while preserving aspect ratio, crop to specific coordinates, and rotate images.

Usage

bash
uv run python .claude/skills/image_resize/resize.py <image_path> [options]

Note: For brevity, examples below use resize.py - prepend the full path .claude/skills/image_resize/ when running.

The script will:

  1. •Open the specified image file
  2. •Optionally crop to specific coordinates
  3. •Optionally rotate by specified angle
  4. •Optionally resize by width and/or height (preserving aspect ratio)
  5. •Save the result with operations in filename

Options

  • •-w, --width - Target width in pixels
  • •--height - Target height in pixels
  • •-c, --crop - Crop box as "left,top,right,bottom" (e.g., "10,10,100,100")
  • •-r, --rotate - Rotation angle in degrees (90, 180, 270, or any angle)
  • •-q, --quality - JPEG quality (1-100, default: 95)

Supported Formats

  • •Input: Any format supported by PIL/Pillow (JPG, PNG, BMP, GIF, WEBP, etc.)
  • •Output: Same format as input

Examples

bash
# Resize to 800px width, auto-calculate height (preserve aspect ratio)
resize.py image.jpg --width 800

# Resize to 600px height, auto-calculate width (preserve aspect ratio)
resize.py image.jpg --height 600

# Resize with both dimensions (scales to fit smaller dimension, preserves aspect)
resize.py image.jpg --width 800 --height 600

# Rotate 90 degrees clockwise
resize.py image.jpg --rotate 90

# Rotate 180 degrees
resize.py image.jpg --rotate 180

# Crop to specific box (left, top, right, bottom)
resize.py image.jpg --crop 10,10,500,400

# Resize and rotate
resize.py image.jpg --width 800 --rotate 90

# Crop, resize, and rotate (operations applied in order: crop → rotate → resize)
resize.py image.jpg --crop 0,0,500,500 --width 300 --rotate 90

# Resize with custom JPEG quality
resize.py photo.jpg --width 1920 --quality 85

Notes

  • •Aspect Ratio: Always preserved when resizing. If both width and height are specified, the image is scaled to fit the smaller dimension.
  • •Rotation: Uses bicubic resampling for smooth results. The canvas expands to fit the rotated image (no cropping).
  • •Crop: Applied first before any other operations. Coordinates are (left, top, right, bottom) in pixels from top-left corner.
  • •Operation Order: Crop → Rotate → Resize
  • •Quality: Only affects JPEG output. Higher values = better quality but larger file size.
  • •Output Naming: Files include operations in the name (e.g., photo_crop_0_0_500_500_rot90_800x533.jpg)

Use Cases

  • •Resizing images for web use while maintaining quality
  • •Creating rotated versions of images
  • •Cropping to specific regions of interest
  • •Batch processing images to specific dimensions
  • •Preparing images for print with exact dimensions

Requirements

  • •Python 3.x
  • •Pillow (PIL) library

The script will automatically install Pillow if it's not available.