How to Resize Images on Mac using Preview and Online Tools

How to Resize Images on Mac using Preview and Online Tools

macOS is a favorite for creatives because it handles images so well. One of the most powerful tools on your Mac is actually one you use every day: Preview.

In this guide, we'll show you how to resize a single image, how to batch resize a dozen at once using Preview, and when you should use a browser-based tool instead.

1. Resizing a Single Image with Preview

1. Open your image in Preview (usually the default if you double-click).
2. Go to the top menu and select Tools > Adjust Size....
3. A dialog box will appear. You can change the width and height by pixels, inches, or percentage.
4. Pro Tip: Make sure the "Scale proportionally" lock icon is closed so your image doesn't get distorted.
5. Click OK and then File > Save (or Cmd+S).

2. Batch Resizing Multiple Images at Once

This is a "hidden" feature of Preview that saves a lot of time.

1. Select all the images you want to resize in Finder.
2. Right-click and select Open with > Preview.
3. Once Preview opens, click inside the sidebar (where the thumbnails are) and press Cmd+A to select all of them.
4. Now, go to Tools > Adjust Size....
5. The changes you make here will be applied to every image you have selected.
6. Click OK, then go to File > Save All.

3. Resizing with imgKonvert (When Speed Matters)

Preview is great, but it can be slow if you're dealing with very large files or if you want to resize and convert to a modern format like WebP at the same time.

1. Go to the imgKonvert Image Resizer.
2. Drag and drop your photos.
3. Set your target dimensions.
4. Click Resize All.
5. Our tool processes everything with a focus on privacy and efficiency.

Why Resize on Mac?

• Email Attachments: High-res iPhone photos are often 5MB+. Resizing them makes sending emails much smoother.
• Web Uploads: If you're a blogger or site owner, huge images will kill your page speed scores.
• Discord/Slack: Stay under the file size limits without needing a premium subscription.

Summary

Mac users have it easy with Preview, which is one of the best built-in image tools on any OS. For more complex workflows, like bulk resizing and format shifting, imgKonvert is a powerful, no-install alternative.