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Terminal.skills
Skills/ImageMagick
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ImageMagick

ImageMagick is a command-line toolkit for converting, resizing, cropping, compositing and inspecting images in over 200 formats. Use it to batch resize photos, convert PNG or SVG to WebP, generate thumbnails, add watermarks, build contact sheets and animated GIFs, or read image metadata with `magick`, `magick mogrify` and `magick identify`.

#image-processing#cli#batch#resize#thumbnail
terminal-skillsv1.1.0
Works with:claude-codeopenai-codexgemini-clicursor
Source
Trust Score
80/ 100
3.83×
Impact

Validation

Score is stale (SKILL.md changed since last review)
Quality
80/ 100
Does it follow best practices?
3 PASS · 3 WEAK
Security
Passed
No known issues
Content review + injection scan
Impact
3.83×
23% → 88% agent success
Avg across 3 eval scenarios
Scored 10/20/2026 · skill v1.1.0
$
✓ Installed imagemagick v1.1.0

Getting Started

  1. Install the skill using the command above
  2. Open your AI coding agent (Claude Code, Codex, Gemini CLI, or Cursor)
  3. Reference the skill in your prompt
  4. The AI will use the skill's capabilities automatically

Example Prompts

  • "Create a responsive landing page layout following our brand guidelines"
  • "Review this component for accessibility issues and suggest fixes"

Documentation

Overview

ImageMagick 7 (current release 7.1.2) is driven by one executable, magick. The old convert, mogrify, identify, compare, montage and composite commands still exist as legacy names in version 6; in 7 call them as magick mogrify, magick identify, magick compare, magick montage. Options are applied left to right, so order matters: settings such as -density must come before the file they affect.

Instructions

Install

bash
brew install imagemagick        # macOS
sudo apt install imagemagick    # Debian/Ubuntu (may still ship 6.x: then use `convert`, `identify`)
magick -version                 # confirm 7.x and the delegates (webp, heic, rsvg)

Basic operations

bash
magick photo.jpg -resize 800x600 out.jpg       # fit inside 800x600, keep ratio
magick photo.jpg -resize 800x600^ out.jpg      # fill 800x600 (one side larger)
magick photo.jpg -resize 50% out.jpg
magick photo.jpg -resize 800x600! out.jpg      # exact size, distorts
magick logo.png -strip -quality 80 logo.webp   # convert, drop metadata
magick -density 300 diagram.svg diagram.png    # density BEFORE the input rasterizes at 300 dpi
magick photo.jpg -crop 500x500+100+50 +repage tile.jpg
magick photo.jpg -auto-orient -resize 1600x1600\> fixed.jpg   # fix EXIF rotation; \> = only shrink

Batch processing

magick mogrify edits files in place, so write to another directory with -path or work on copies.

bash
mkdir -p resized
magick mogrify -path resized -auto-orient -resize 1200x1200\> -quality 85 *.jpg

for f in *.png; do magick "$f" -quality 80 "${f%.png}.webp"; done

mkdir -p thumbnails
for f in images/*.jpg; do
  magick "$f" -auto-orient -resize 200x200^ -gravity center -extent 200x200 "thumbnails/$(basename "$f")"
done

Compositing and effects

bash
magick photo.jpg -gravity southeast -fill 'rgba(255,255,255,0.5)' -pointsize 24 \
  -annotate +10+10 '© 2026 Harbor Studio' watermarked.jpg
magick photo.jpg badge.png -gravity southeast -geometry +20+20 -composite badged.jpg
magick montage images/*.jpg -geometry 200x200+5+5 -tile 4x3 contact-sheet.jpg
magick -delay 50 -loop 0 frame_*.png animation.gif
magick compare -metric AE before.png after.png diff.png   # prints number of differing pixels

Inspect

bash
magick identify photo.jpg                          # name, format, size, depth, colorspace
magick identify -format '%w x %h\n' photo.jpg
magick identify -list format | grep -i webp        # is a format supported?

Chaining without temp files

bash
magick photo.jpg -resize 50% png:- | magick png:- -colorspace Gray gray.png

Name the format on the pipe (png:-); a bare - does not tell ImageMagick what to write. The upstream hardened policy sets path rights to none for -, so pipes fail under it ("not authorized"); use temp files there.

Examples

Example 1: "Make 300px WebP thumbnails of every photo in ./uploads"

bash
mkdir -p thumbs
for f in uploads/*.{jpg,jpeg,png}; do
  [ -e "$f" ] || continue
  magick "$f" -auto-orient -thumbnail 300x300^ -gravity center -extent 300x300 -strip -quality 80 \
    "thumbs/$(basename "${f%.*}").webp"
done

Result: thumbs/ holds square 300x300 WebP files, rotated upright, with EXIF removed. -thumbnail is -resize plus metadata stripping, optimized for small sizes.

Example 2: "Create a 1200x630 social card for my blog post"

bash
magick -size 1200x630 gradient:'#667eea-#764ba2' \
  -gravity center -fill white -font DejaVu-Sans-Bold \
  -pointsize 56 -annotate +0-40 'Shipping Postgres Upgrades Safely' \
  -pointsize 26 -annotate +0+50 'harborstudio.dev/blog' og-image.png
magick identify og-image.png     # og-image.png PNG 1200x630 ...

If the font name is rejected, pick one from magick -list font.

Guidelines

  • Untrusted images: tighten policy.xml (check the active one with magick identify -list policy). The upstream hardened policy caps memory, area and disk, and allows only GIF, JPEG, PNG and WEBP; run in a sandbox for user uploads. Many distributions already block PDF/PS/EPS in policy.xml, so magick doc.pdf[0] page.jpg can fail with "attempt to perform an operation not allowed by the security policy". PDF also needs Ghostscript.
  • Cap resources in batch jobs: -limit memory 256MiB -limit disk 1GiB.
  • mogrify overwrites originals unless you pass -path; test on copies first.
  • Use -auto-orient before resizing phone photos, and -strip before publishing (removes EXIF location data).
  • Use +repage after -crop so a stale canvas offset does not leak into the output (especially GIF/PNG).
  • Prefix user-supplied filenames with ./ so a name starting with - is not read as an option.
  • For massive concurrent web workloads, libvips (vips) uses less memory; ImageMagick wins on breadth of operations and formats.