How to Resize a Photo on a Mac

Charlotte Daniels

Mac, Tutorials

Photographs often need to be resized for various purposes, such as uploading them to websites or sending them via email. If you’re a Mac user, resizing photos can be done easily using the built-in Preview application. In this tutorial, we’ll show you how to resize a photo on a Mac using Preview.

Step 1: Open the Photo in Preview

To start, locate the photo you want to resize on your Mac and double-click it. This will open the photo in the default image viewer, which is usually Preview.

Step 2: Access the Tools

Once the photo is open in Preview, go to the top menu bar and click on “Tools”. A drop-down menu will appear with various options.

Step 3: Select “Adjust Size”

In the “Tools” menu, scroll down and select “Adjust Size”. This will open a dialog box with options to resize your photo.

Step 4: Specify the New Dimensions

In the “Adjust Size” dialog box, you’ll see two fields labeled “Width” and “Height”. By default, these fields display the current dimensions of your photo in pixels.

  • If you want to resize your photo while maintaining its aspect ratio, enter either a new width or height value.

    The other value will automatically adjust proportionally.

  • If you want to resize your photo without maintaining its aspect ratio, uncheck the checkbox labeled “Scale proportionally”. This will allow you to freely enter new values for both width and height.


  • To maintain image quality, make sure to enter values that are larger than the original dimensions. Enlarging a photo may result in loss of quality.
  • To reduce the file size, enter values that are smaller than the original dimensions. This can be useful when you want to email or upload the photo to a website.

Step 5: Save the Resized Photo

Once you’ve specified the new dimensions for your photo, click on the “OK” button in the “Adjust Size” dialog box. The photo will now be resized according to your specifications.


  • If you want to keep the original photo intact, make sure to save the resized photo with a different name or in a different location.
  • To overwrite the original photo, simply use the “Save” option in Preview. However, this is not recommended unless you have a backup of the original photo.

Congratulations! You have successfully resized a photo on your Mac using Preview. Resizing photos can come in handy for various purposes, so knowing how to do it quickly and easily is a valuable skill!

Remember, Preview offers many other useful features for editing and enhancing photos, so feel free to explore and experiment with its capabilities.

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