Batch Resize Images on Mac with Preview
You can easily batch resize groups of images within Mac OS X by using the included Preview app, that is, taking a group of pictures set at one or various resolutions, and collectively resize them all together in a group to a new resolution, outputting either as the same file or as a new file saved at the newly desired resolution. Long ago you had to buy expensive third party software for this purpose, but no longer is there a need for any additional downloads or expensive photo editing applications to perform these tasks on a Mac. Instead you only need Preview, which is free with every Mac and every version of OS X! Here’s how to use Previews’ powerful yet easy batch image resize feature it in a few simple steps.
Batch Resize Images in Mac OS X
You will need to launch Preview, which is in the /Applications/ folder, but is also usually the default image editor and can be typically opened by just opening any picture. Once Preview is open, proceed:
- Select all the images you want resized and open them within Preview
- From Preview, select the images that you want to batch resize from the drawer (Command+A will select them all)
- Now, go to the menu labeled Tools, and then Adjust Size
- Enter a value for what you want the new width and height to be
- Next, navigate to the File menu and click “Save All” or, to save a NEW version that is resized, choose “Export Selected Images…” or “Save As”
Choose a path to save the files in the Save dialog to if you’re exporting or using “Save As” features, then just wait for all of the images to finish resizing to their new resolutions. The batch resizing takes place fairly quick, but the precise speed is dependent on your available system resources and speed of the Mac.
This works in Preview that is included in virtually all versions of Mac OS X, happy batch resizing!
Updated: 4/21/2014 for clarification, the precise language varies slightly per version of OS X but the procedure works in all Previews versions, whether it’s Snow Leopard, OS X Lion, OS X Mountain Lion OS X Mavericks, and beyond.