Using imagemagick to crop and resize 100+ photos

I've been trying to learn Spanish lately! I'm trying something new this time: playing a game in Spanish, taking photos of dialogue that I should study, and turning those photos into Anki flashcards.

Lately, I've been playing Pokémon Platino, a Latin American Spanish patch for Pokémon Platinum on the DS.

The problem is that when I take photos with my phone, they're (1) in high resolution, and (2) taken in portrait mode, meaning there's a lot of wasted space. Across hundreds of photos, these issues mean storage will become an issue quickly.

Given the sheer quantity and size of the photos (sometimes 100+ at a time!), I'm definitely not gonna manually crop each photo. There aren't many free options online, either.

Luckily, there's an easy solution to both of these problems!

Bulk cropping and resizing with imagemagick

imagemagick is a popular photo processing command-line tool. It allows for bulk, in-place image cropping and resizing, and as a CLI tool, we can write a script too!

if "%1"=="" goto argerr

magick.exe mogrify -crop 3472x2601+0+950 -resize 400x300 %1\*.jpg
@echo Done!
goto :eof

:argerr
@echo Requires a path argument!
exit /B 1

This Windows batch file requires an argument, which points to a directory containing images taken from my phone. The magick.exe line first crops the top and bottom out of the image, and then resizes what's left into a 400 x 300 image.

This process converts images of about 4.50 MB down to less than 100 KB! On average, this reduces the total storage size by 95%!!!

To crop and resize all images in new-photos, just run the script like so:

> optimize.bat .\new-photos\