How to Batch Resize Images Without a Photo Editing Program on Your Mac

By Alexia Petrakos

Included with Mac OSX Tiger is a program called "Automator," which allows you to create your own mini-programs using various actions from many of the programs on your Apple computer. You can create a program on your Mac to back up a set of folders with one click, or gather all the URLs from a specific Web page and even batch resize images without a graphics program. You may need to resize all 200 super-high-resolution photos you took on your vacation to Costa Rica to make them a manageable size for uploading to your photo-sharing account. Resizing 200 images manually is a huge chore, and if you don't have a fancy photo-editing program, you'll not be able to take advantage of batch processing.Here are the steps to create your own program in Automator to batch resize images you've selected, save them to a specific folder and rename them without a photo-editing program such as Adobe Photoshop.

Things You'll Need

  • Apple computer running Mac OSX Tiger

Step 1

Launch Automator. It will be in your Applications folder. You can access this from your dock or by opening up a new Finder window and navigating to the Applications folder.

Step 2

Click on "Finder" in the Library column on the far left of the Automator window.

Step 3

Drag the "Ask for Finder Items" action from the middle column over to the right to the area that says "Drag or add actions here to build your workflow."

Step 4

Type in "Choose the Images to Resize:" in the Prompt field and make sure the "Allow Multiple Selection" check box is checked. This step tells the Automator Workflow to open a Finder window in Mac OSX Tiger so you can select the images you want to resize. The Prompt is what will appear in the title bar of that window.

Step 5

Drag over the "Rename Finder Items" action from the Action list and place it under the "Ask for Finder Items" action that you just added in Step 3.

Step 6

Click "Add" on the Warning that pops up. This will add a "Copy Finder Items" action, as well as the "Rename Finder Items" action so that your original images are preserved just in case you need them later.

Step 7

Select the directory where you want to save all your resized images. It can be directly on the desktop, or you can create another folder to keep all of them in one place. In the "To" drop-down in this action, select "Other" and navigate to the folder where you want to keep all your resized images.

Step 8

Select "Add Text" in the first drop-down box of the "Rename Finder Items" box in your Automator Workflow.

Step 9

Type "resized" in the "Add" field. This will add the word "resized" to the end of each image file name.

Step 10

Click on "Preview" in the Library column on the far left. This will bring up the actions available using the "Preview" PDF and image viewer application that came with your Apple computer.

Step 11

Drag over the "Scale Images" action from the middle "Action" column to your workflow.

Step 12

Select "By Percentage" in the drop-down menu and type "50" in the text box next to the drop-down. You can scale the images to a specific size in pixels instead if you prefer.

Step 13

Test your workflow by hitting the "Run" button at the top right of the Automator window.

Step 14

Select your images from the Finder window that pops up and let the program run.

Step 15

If everything worked properly, each step in your Workflow window should have a light green checkmark in the lower-left corner.

Step 16

Open the folder you specified to store the resized images. All the images you selected should be there, and they should be resized. You can check this by right-clicking each item and selecting "Info"-the size of the image is in the "More Info" section of this window. If the images are not in the folder or the program fails, go back over each step and double-check your actions.

Step 17

Save your workflow by selecting "File" > "Save As." Name your new mini-program "Batch Resize" or something similar and save it to your desktop so you'll have easy access to it. Next time you need to resize lots of images, just double-click your new program and let it run. Congratulations! You just made your very own program on your Apple computer in Mac OSX Tiger!

Tips & Warnings

  • Play around with workflow; there are lots of things you can do, including backing up your folders to an external hard drive or even an FTP server.
  • If you ever need to edit the Batch Resize workflow you created, expand the "My Workflows" folder in the Library list in Automator and drag it over just as you did in creating each step of this workflow. All the steps show up, and you can alter them if you need to.