imagemagick

CLI

Create, edit, and convert images from the command line.

13 views

Installation

Homebrewbrew install imagemagick

ImageMagick

Batch convert, resize, and manipulate images

When to use

Image format conversion, resizing, or batch processing

Examples

Convert PDF to image🟢 94% success

convert -density 150 input.pdf output.png

⚠ Common failures (2)

Blurry/low resolution output → -density option is required; use -density 150 or higher before the input file
Policy error: not authorized → Edit /etc/ImageMagick-6/policy.xml and change PDF rights from 'none' to 'read|write'

Fallback:pdftoppm -r 150 input.pdf output

Resize image to percentage🟢 99% success

convert input.jpg -resize 50% output.jpg

Resize image to exact dimensions🟢 98% success

convert input.jpg -resize 800x600! output.jpg

⚠ Common failures (1)

Aspect ratio changed unexpectedly → Use 800x600 without ! to keep aspect ratio, or 800x to fix only width

Batch convert PNG to JPEG🟢 91% success

convert '*.png' -quality 85 'output_%d.jpg'

⚠ Common failures (1)

Only one file converted → Use mogrify instead: mogrify -format jpg -quality 85 *.png

Fallback:mogrify -format jpg -quality 85 *.png