Libvips Image

High-performance image processing with libvips. Use for resizing, converting, watermarking, thumbnails, and batch image operations with low memory usage.

Security Scan

The skill is internally consistent with an image-processing purpose — it includes install and runtime scripts for libvips/pyvips and does not request credentials — but the installer uses a downloadable install helper (curl|sh) which is a moderate installation-time risk that you should review before running.

Purpose & Capability

Name/description (libvips image processing) align with included files: vips_tool.py, vips_batch.py, test script, and an installer. All code implements image operations (resize, convert, watermark, batch processing) and dependencies (pyvips/libvips) are expected.

Instruction Scope

SKILL.md and run.sh direct only image-processing actions and installation steps. They do ask you to run scripts/install.sh which modifies system packages and installs pyvips; documentation references Windows install.ps1 and run.bat that are not present in the bundle (doc/code mismatch). Instructions do not attempt to read unrelated credentials or system config.

Install Mechanism

There is no registry install spec, but scripts/install.sh is provided and performs package-manager installs (apt/dnf/pacman/apk/brew) which require sudo. The script may download and execute an external installer for 'uv' via curl/wget piped to sh (https://astral.sh/uv/install.sh). Downloading-and-executing remote scripts is a moderate-to-high risk and should be reviewed/verified before running.

Credentials

The skill declares no required env vars or credentials. install.sh honors optional env flags (AUTO_MODE, VERBOSE, SKIP_SUDO) only. No hidden credential exfiltration or requests for unrelated secrets were found.

Persistence & Privilege

Skill is not marked always:true and is user-invocable. It does not request to modify other skills or system settings beyond typical installation (package installs, PATH adjustments). No autonomous escalation flags were detected.

Scan Findings in Context

[curl_pipe_sh] expected: scripts/install.sh may run curl -LsSf https://astral.sh/uv/install.sh | sh (or wget -qO- ... | sh) to install the 'uv' helper. Installing a helper from a remote script is consistent with the install flow but is a risky install mechanism; review the external installer before execution.

Assessment

This skill appears to do what it says: image processing with libvips/pyvips. Before installing or running install.sh: 1) Review scripts/install.sh line-by-line (it runs package manager commands and may invoke sudo). 2) Avoid blindly piping remote scripts to sh; if the script wants to install 'uv' from https://astral.sh, manually inspect that URL or install uv via a trusted channel first. 3) Because the installer runs system package installs, run it in a disposable environment (container or VM) or use SKIP_SUDO=1/AUTO_MODE where appropriate. 4) Note the SKILL.md references Windows .ps1/.bat installers that are not included — if you need Windows support, ask the author for the missing files. 5) No credentials are requested by the skill. If you’re uncomfortable with the remote install step, you can manually install libvips and pyvips and then use the provided scripts without running the remote installer.

libvips Image Processing

Fast, memory-efficient image processing using libvips via pyvips. Supports 300+ operations including resize, crop, rotate, convert, watermark, composite, and more. Ideal for batch processing large images.

When to Use

• Resize, crop, or thumbnail images efficiently
• Convert between formats (JPEG, PNG, WebP, AVIF, HEIC, TIFF, PDF, SVG)
• Add watermarks or text overlays
• Batch process multiple images
• Handle large images with low memory usage
• Create image pipelines for web optimization

Quick Start

Install (One-Click)

# Recommended: Auto-detect OS and install everything
./scripts/install.sh

The install script will:

1. Detect your OS (macOS, Linux, Windows)
2. Install libvips system library
3. Install pyvips via uv (preferred) or pip
4. Verify the installation

Manual Install

macOS (Homebrew):

brew install vips
uv pip install pyvips  # preferred
# or: pip install pyvips

Ubuntu/Debian:

sudo apt-get install libvips-dev
uv pip install pyvips  # preferred
# or: pip install pyvips

Fedora/RHEL:

sudo dnf install vips-devel
uv pip install pyvips

Arch Linux:

sudo pacman -S libvips
uv pip install pyvips

Windows (PowerShell, recommended):

# One-click install (downloads libvips + installs pyvips)
.\scripts\install.ps1

Windows (Manual):

# Option 1: winget (if available)
winget install libvips.libvips

# Option 2: scoop
scoop install libvips

# Option 3: Manual download
# Download from https://github.com/libvips/libvips/releases
# Extract to C:\vips or %LOCALAPPDATA%\vips
# Add bin\ to PATH

# Install pyvips
uv pip install pyvips
# or: pip install pyvips

Install uv (if not installed):

# macOS/Linux
curl -LsSf https://astral.sh/uv/install.sh | sh

# Windows (PowerShell)
irm https://astral.sh/uv/install.ps1 | iex

Basic Usage

macOS/Linux - Using run.sh wrapper (recommended):

./scripts/run.sh vips_tool.py resize input.jpg output.jpg --width 800
./scripts/run.sh vips_tool.py convert input.jpg output.webp --quality 85
./scripts/run.sh vips_tool.py thumbnail input.jpg thumb.jpg --size 200
./scripts/run.sh vips_batch.py resize ./input ./output --width 800

Windows - Using run.bat wrapper (recommended):

.\scripts\run.bat vips_tool.py resize input.jpg output.jpg --width 800
.\scripts\run.bat vips_tool.py convert input.jpg output.webp --quality 85
.\scripts\run.bat vips_tool.py thumbnail input.jpg thumb.jpg --size 200
.\scripts\run.bat vips_batch.py resize .\input .\output --width 800

Cross-platform - Using uv (after uv sync):

uv run python scripts/vips_tool.py resize input.jpg output.jpg --width 800

Direct Python (if library paths are configured):

python scripts/vips_tool.py resize input.jpg output.jpg --width 800
python scripts/vips_tool.py convert input.jpg output.webp --quality 85
python scripts/vips_tool.py thumbnail input.jpg thumb.jpg --size 200
python scripts/vips_tool.py watermark input.jpg output.jpg --text "Copyright 2024"

Supported Formats

Format	Read	Write	Notes
JPEG	Yes	Yes	Quality 1-100
PNG	Yes	Yes	Compression 0-9
WebP	Yes	Yes	Lossy/lossless
AVIF	Yes	Yes	Modern, high compression
HEIC	Yes	Yes	Apple format
TIFF	Yes	Yes	Multi-page support
GIF	Yes	Yes	Animated support
PDF	Yes	Yes	Via poppler
SVG	Yes	No	Via librsvg
RAW	Yes	No	Via libraw

Operations

1) Resize

Resize images with various fit modes.

# Resize to exact width, maintain aspect ratio
python scripts/vips_tool.py resize input.jpg output.jpg --width 800

# Resize to exact height
python scripts/vips_tool.py resize input.jpg output.jpg --height 600

# Resize to fit within bounds
python scripts/vips_tool.py resize input.jpg output.jpg --width 800 --height 600

# Resize to cover (fill) dimensions
python scripts/vips_tool.py resize input.jpg output.jpg --width 800 --height 600 --mode cover

# Force exact dimensions (may distort)
python scripts/vips_tool.py resize input.jpg output.jpg --width 800 --height 600 --mode force

Resize modes:

• fit (default): Fit within bounds, maintain aspect ratio
• cover: Cover bounds, crop excess
• force: Force exact dimensions

2) Thumbnail

Create optimized thumbnails with smart cropping.

# Square thumbnail
python scripts/vips_tool.py thumbnail input.jpg thumb.jpg --size 200

# Attention-based smart crop
python scripts/vips_tool.py thumbnail input.jpg thumb.jpg --size 200 --crop attention

# Center crop
python scripts/vips_tool.py thumbnail input.jpg thumb.jpg --size 200 --crop centre

Crop strategies:

• none: No cropping, fit within size
• centre: Crop from center
• attention: Smart crop focusing on interesting areas
• entropy: Crop to maximize entropy

3) Convert

Convert between image formats with quality control.

# JPEG to WebP
python scripts/vips_tool.py convert input.jpg output.webp --quality 85

# PNG to AVIF (modern format, great compression)
python scripts/vips_tool.py convert input.png output.avif --quality 50

# JPEG to PNG (lossless)
python scripts/vips_tool.py convert input.jpg output.png

# With compression level for PNG
python scripts/vips_tool.py convert input.jpg output.png --compression 9

4) Crop

Extract a region from an image.

# Crop 400x300 region starting at (100, 50)
python scripts/vips_tool.py crop input.jpg output.jpg --left 100 --top 50 --width 400 --height 300

# Smart crop to aspect ratio
python scripts/vips_tool.py crop input.jpg output.jpg --width 800 --height 600 --smart

5) Rotate

Rotate images by any angle.

# Rotate 90 degrees clockwise
python scripts/vips_tool.py rotate input.jpg output.jpg --angle 90

# Rotate 45 degrees with background color
python scripts/vips_tool.py rotate input.jpg output.jpg --angle 45 --background "255,255,255"

# Auto-rotate based on EXIF
python scripts/vips_tool.py rotate input.jpg output.jpg --auto

6) Watermark

Add text or image watermarks.

# Text watermark
python scripts/vips_tool.py watermark input.jpg output.jpg --text "Copyright 2024"

# Position: top-left, top-right, bottom-left, bottom-right, center
python scripts/vips_tool.py watermark input.jpg output.jpg --text "Logo" --position bottom-right

# With opacity
python scripts/vips_tool.py watermark input.jpg output.jpg --text "Draft" --opacity 0.3

# Image watermark
python scripts/vips_tool.py watermark input.jpg output.jpg --image logo.png --position bottom-right --opacity 0.5

7) Composite

Combine multiple images.

# Overlay image on background
python scripts/vips_tool.py composite background.jpg overlay.png output.jpg

# With position offset
python scripts/vips_tool.py composite background.jpg overlay.png output.jpg --x 100 --y 50

# With blend mode
python scripts/vips_tool.py composite background.jpg overlay.png output.jpg --blend multiply

Blend modes: over, multiply, screen, overlay, darken, lighten

8) Adjust

Adjust brightness, contrast, saturation.

# Increase brightness
python scripts/vips_tool.py adjust input.jpg output.jpg --brightness 1.2

# Increase contrast
python scripts/vips_tool.py adjust input.jpg output.jpg --contrast 1.3

# Increase saturation
python scripts/vips_tool.py adjust input.jpg output.jpg --saturation 1.5

# Combine adjustments
python scripts/vips_tool.py adjust input.jpg output.jpg --brightness 1.1 --contrast 1.2 --saturation 1.1

9) Sharpen

Apply sharpening filter.

# Default sharpen
python scripts/vips_tool.py sharpen input.jpg output.jpg

# Custom sigma (blur radius)
python scripts/vips_tool.py sharpen input.jpg output.jpg --sigma 1.5

# Custom parameters
python scripts/vips_tool.py sharpen input.jpg output.jpg --sigma 1.5 --x1 2 --m2 3

10) Blur

Apply Gaussian blur.

# Default blur
python scripts/vips_tool.py blur input.jpg output.jpg

# Custom sigma
python scripts/vips_tool.py blur input.jpg output.jpg --sigma 5

11) Flip & Mirror

Flip images horizontally or vertically.

# Horizontal flip (mirror)
python scripts/vips_tool.py flip input.jpg output.jpg --horizontal

# Vertical flip
python scripts/vips_tool.py flip input.jpg output.jpg --vertical

12) Grayscale

Convert to grayscale.

python scripts/vips_tool.py grayscale input.jpg output.jpg

13) Info

Get image metadata.

python scripts/vips_tool.py info input.jpg

Output:

File: input.jpg
Format: jpeg
Width: 3840
Height: 2160
Bands: 3
Interpretation: srgb
Size: 2.4 MB

Batch Processing

Process multiple images at once.

# Resize all JPEGs in a directory
python scripts/vips_batch.py resize ./input ./output --width 800 --pattern "*.jpg"

# Convert all images to WebP
python scripts/vips_batch.py convert ./input ./output --format webp --quality 85

# Create thumbnails for all images
python scripts/vips_batch.py thumbnail ./input ./thumbnails --size 200

# Custom batch with JSON config
python scripts/vips_batch.py --config batch_config.json

Batch Config Format

{
  "input_dir": "./input",
  "output_dir": "./output",
  "operations": [
    {"type": "resize", "width": 1920},
    {"type": "sharpen", "sigma": 0.5},
    {"type": "convert", "format": "webp", "quality": 85}
  ],
  "pattern": "*.{jpg,jpeg,png}",
  "recursive": true,
  "workers": 4
}

Python API

Basic Usage

import pyvips

# Load image
image = pyvips.Image.new_from_file("input.jpg")

# Resize
resized = image.resize(0.5)  # 50% scale
resized = image.thumbnail_image(800)  # 800px width

# Save
resized.write_to_file("output.jpg", Q=85)  # JPEG quality 85
resized.write_to_file("output.webp", Q=85)  # WebP quality 85

Chaining Operations

import pyvips

# Load, process, save in one pipeline
image = pyvips.Image.new_from_file("input.jpg", access="sequential")
result = (
    image
    .thumbnail_image(1200)
    .sharpen(sigma=0.5)
    .write_to_file("output.webp", Q=85)
)

Watermark with Text

import pyvips

image = pyvips.Image.new_from_file("input.jpg")

# Create text overlay
text = pyvips.Image.text(
    "Copyright 2024",
    font="sans 24",
    rgba=True
)

# Composite at bottom-right
x = image.width - text.width - 20
y = image.height - text.height - 20
result = image.composite2(text, "over", x=x, y=y)
result.write_to_file("output.jpg")

Batch Processing

import pyvips
from pathlib import Path
from concurrent.futures import ThreadPoolExecutor

def process_image(input_path, output_dir, width=800):
    image = pyvips.Image.new_from_file(str(input_path), access="sequential")
    thumbnail = image.thumbnail_image(width)
    output_path = output_dir / f"{input_path.stem}.webp"
    thumbnail.write_to_file(str(output_path), Q=85)
    return output_path

input_dir = Path("./input")
output_dir = Path("./output")
output_dir.mkdir(exist_ok=True)

files = list(input_dir.glob("*.jpg"))
with ThreadPoolExecutor(max_workers=4) as executor:
    results = executor.map(lambda f: process_image(f, output_dir), files)

CLI Parameters

Parameter	Description	Default
--width	Target width in pixels	-
--height	Target height in pixels	-
--size	Thumbnail size (square)	200
--quality	Output quality (1-100)	85
--compression	PNG compression (0-9)	6
--mode	Resize mode: fit, cover, force	fit
--crop	Crop strategy	none
--angle	Rotation angle in degrees	0
--sigma	Blur/sharpen radius	1.0
--opacity	Watermark opacity (0-1)	0.5
--position	Watermark position	bottom-right
--workers	Batch processing threads	4
--pattern	File glob pattern	.
--recursive	Process subdirectories	false

Performance Tips

Tip	Description
Sequential access	Use access="sequential" for streaming
Pipeline operations	Chain operations before writing
Parallel processing	Use ThreadPoolExecutor for batches
Format selection	WebP/AVIF for web, JPEG for photos
Quality settings	85 for quality, 75 for size
Thumbnail vs resize	thumbnail_image is faster for downscaling

Memory Usage

libvips uses a streaming architecture:

• Only loads pixels when needed
• Processes images in small chunks
• Memory usage independent of image size
• 10-100x less memory than ImageMagick/PIL for large images

Troubleshooting

Common Issues

Issue	Solution
"Cannot find libvips"	Install via brew/apt, check PATH
Slow processing	Use sequential access, check disk I/O
Memory errors	Increase cache, reduce workers
Format not supported	Install optional dependencies
Poor quality	Increase quality parameter
HEIC not working	Install libheif: brew install libheif
SVG not rendering	Install librsvg: brew install librsvg

Windows-Specific Issues

Issue	Solution
"cannot load library 'libvips-42.dll'"	Add vips bin\ folder to PATH
DLL not found after install	Restart terminal/PowerShell
winget install fails	Use manual download or scoop
Permission denied	Run PowerShell as Administrator
PATH not updated	Log out and log back in, or restart

Windows PATH Setup (Manual):

# Add to current session
$env:PATH = "C:\vips\bin;$env:PATH"

# Add permanently (run as Admin or for current user)
[Environment]::SetEnvironmentVariable("PATH", "C:\vips\bin;$env:PATH", "User")

macOS-Specific Issues

Issue	Solution
"cannot load library 'libvips.42.dylib'"	Use ./scripts/run.sh wrapper
DYLD_LIBRARY_PATH not working	macOS SIP blocks env vars; use run.sh
Homebrew Python issues	Use /opt/homebrew/bin/python3 directly

macOS Library Path Setup:

# Add to ~/.zshrc or ~/.bashrc
export DYLD_LIBRARY_PATH="/opt/homebrew/lib:$DYLD_LIBRARY_PATH"

Linux-Specific Issues

Issue	Solution
Package not found	Check distro-specific package name
ldconfig issues	Run sudo ldconfig after install
Permission denied	Use sudo for system packages