ImageMagick CLI

Overview

Use ImageMagick’s magick CLI to perform deterministic image transforms and batch processing. When choosing options or flags, consult references/imagemagick-cli.md first; use other references for task-specific depth.

Default preferences:

• Prefer magick ... output.ext for safe “read → transform → write”.
• Use magick mogrify only when you explicitly want in-place edits (or use -path out/).
• For any image you touch, capture file size before and after, and report the before/after sizes plus percent reduction.

Quick Start (most common)

# Convert formats
magick input.jpg output.png

# Resize (keep aspect ratio)
magick input.jpg -resize 1200x1200 output.jpg

# Strip metadata (EXIF/ICC/comments)
magick input.jpg -strip output.jpg

# Auto-orient based on EXIF, then strip
magick input.jpg -auto-orient -strip output.jpg

# Web-friendly JPEG (quality + strip)
magick input.png -colorspace sRGB -quality 82 -strip output.jpg

# Web-friendly AVIF baseline (if AVIF/HEIC coder available)
magick input.jpg -auto-orient -resize "2048x2048>" -colorspace sRGB -quality 45 -define heic:speed=6 -strip output.avif

Workflow: Choose the Right Tool

• Use magick ... output.ext for safe transforms that preserve the input file.
• Use magick mogrify ... *.ext for bulk edits; it can overwrite originals.
• Use magick identify to inspect images or extract metadata (scriptable output).
• Use magick montage for contact sheets / grids.
• Use magick composite for overlaying images (watermarks, badges).

Core Patterns

Inspect images (before deciding options)

# Human-readable summary
magick identify input.png

# Verbose (debug what’s actually in the file)
magick identify -verbose input.png

# Scriptable fields
magick identify -format "%m %wx%h %z-bit %[colorspace]\n" input.png

Batch processing safely

Prefer writing to a new directory over in-place edits:

# Example pattern: loop in your shell (don’t use mogrify unless requested)
mkdir -p out
for f in *.jpg; do
  magick "$f" -auto-orient -resize "1600x1600>" -strip "out/$f"
done

If you must do batch edits, consider mogrify -path:

magick mogrify -path out -auto-orient -resize "1600x1600>" -strip *.jpg

Geometry and parentheses

• Quote geometry arguments containing < or > (shell redirection).
• On POSIX shells, parentheses must be escaped as \( and \) (Windows differs).

For a geometry cheat sheet and “cover/crop/letterbox” patterns, read references/geometry.md.

References (read when needed)

• references/imagemagick-cli.md: preferred, comprehensive CLI reference (read first for syntax, options, and command behavior).
• references/recipes.md: practical commands for common tasks (web, overlays, montage, batch).
• references/avif.md: AVIF/HEIC-specific recipes + tuning knobs.
• references/geometry.md: geometry operators and cropping/extent patterns.
• references/security.md: policy/resource-limit guidance for untrusted inputs.
• references/official-docs.md: canonical docs + Context7 lookup guidance.

Troubleshooting checklist

• If an option is interpreted as a filename, enable pedantic option parsing: -define registry:option:pedantic=true
• If output looks wrong, run magick identify -verbose ... and confirm colorspace/alpha/orientation.
• If processing is slow or memory-heavy, resize earlier and review resource limits / policy.