Generating thumbnails with MacOS Automator
May 4, 2017
2 minute read

Create a simple Finder service with MacOS Automator which is capable of generating thumbnails for a wide assortment of image file types. This service saves all generated thumbnail files into a dedicated folder inside the source folder.

To begin start Automator click File then New, select Service and click Choose.

automator service

This will open a new empty service window. On the left will be all of the available actions. These can be dragged into place to create the automator service.

This automation service consists of 3 steps.

  1. Determine the source folder with the images.
  2. Create a destination folder inside the source folder.
  3. Copy selected image files into the destination folder and scale them.

The input for the Automator service will be the selected image files in Finder. These are passed as input to a shell script which returns the full path of the selected image files. The location is then set as the value of the Path variable.

determining the source folder path

Next the service creates a new folder (called low in this example) inside the source folder stored in the Path variable. The destination folder path is then set as the value of the Storage variable.

create destination folder

The last step copies all of the selected image files into the destination folder stored in the Storage variable. The copied images are then scaled to the specified width (128px in this example).

copy and scale image files

Save the service as Create Thumbnails.

To use, select any image or images in Finder, right click and select Create Thumbnails.

run service