Batch Resize

Why

As of 2018, the OSE wiki has a strict upper file size limit of 1M as our OSE Server infrastructure is operating on a very limited budget. For more information on why this is necessary, see Mediawiki#$maxUploadSize

These commands can trivialize the process of doing a bulk resize of images before uploading to the wiki.

Imagemagick

All it takes is one line to resize a directory full of images to your desired size if you have the ImageMagick tools package installed. convert is a tool that comes with that package.

To install ImageMagick, go to Terminal and type: (on Debian/Ubuntu based systems)

sudo apt-get install imagemagick

To resize only, go to the directory of interest and execute a command using find and convert, like so:

Note: This will permanently alter all of your image files! Make sure to copy your image files to a duplicate 'working' directory before running this command. Do not run these commands in the directory where your original files live.

# most robust; handles portrait & landscape images of various dimensions
# 786433 = 1024*768+1
find . -maxdepth 1 -iname '*.jpg' -exec convert {} -resize '786433@>' {} \;

# or use this if all the photos are the same orientation
find . -maxdepth 1 -iname '*.jpg' -exec convert {} -resize 1024x768 {} \;

To resize and convert to another format (example converts JPEG to PNG):

find . -iname '*.jpg' -exec convert {} -resize 640x480 {}.png \;

mogrify

Go into Terminal and change directory to folder with your pictures with whatever percentage reduction yuou need - here it is 25%:

mogrify -resize 50% * -format jpg *

To switch to another format - jpg may be replaced with other formats.

mogrify -resize 50% -format jpg *

Notes

6/25 - installed with sudo apt install graphicsmagick-imagemagick-compat

Links

• http://bdhacker.wordpress.com/2011/01/04/resize-multiple-images-in-a-folder-batch-image-resize-in-ubuntu/
• http://www.imagemagick.org/Usage/basics/#mogrify