How to compress images in bulk on iOS/iPadOS

Earlier this year I have shared a tweet about compressing images on iOS and iPadOS using a shell app. The tweet has received a fair amount of interest so far and to further help people looking for the matter, I have decided to write a short blog post about it.

how to compress images on iOS/iPadOS:

1. download @iSH_app
2. apk add ImageMagick
3. mkdir -p /mnt/icloud_drive
4. mount -t ios . /mnt/icloud_drive
5. cd /mnt/icloud_drive
6. convert -format "jpg" -quality "75" old.jpg new.jpg@a_Shell_iOS has ‘convert’ built-in btw

— @pirafrank@mastodon.social (@pirafrank) January 25, 2021

It’s worth pointing out that there are a couple of other ways to do that. Images can be compressed using the pre-installed Shortcuts app, as pointed out in the tweet thread, or by using an online service. By the way, a shell approach may be helpful to reuse a script you already have, do some batch processing and protect your privacy (you don’t need to upload pictures anywhere).

Prerequisites:

1. Download the @iSH_app
2. add Alpine repositories (link)

and install the ImageMagick package:

apk add imagemagick

mount and convert!

Time to convert. But before I show you how to mount an external path, thanks to the awesome iSH app. It is a good option to read/write images straight where you need them. For example, you could use it with apps such as Secure ShellFish or FileBrowser Pro. In the example below, I use iCloud Drive which we all have:

1. mkdir -p /mnt/icloud_drive
2. mount -t ios . /mnt/icloud_drive
3. cd /mnt/icloud_drive

Since ImageMagick is now installed, we can use the same commands and options we are used to:

convert -format "jpg" -quality "75" old.jpg new.jpg

That’s it!

Thanks for reading. Hope it helps!