How to Change the Size of an Image on a Mac

When working with images, it's common to need to resize them for various purposes, such as using them in an email signature or uploading them to a website. Fortunately, the Preview application that comes pre-installed on every Mac makes it easy to change the size of an image.

To restore an image to its original resolution, simply press Command Z or select Edit | Undo Size Change from the menu. This will undo any previous resizing changes you may have made.

If you need to resize an image, follow these steps:

1. Open the image in Preview by right-clicking on it and selecting Open With | Preview.

2. Select Tools | Adjust Size… from the menu or use the keyboard shortcut (see below).

3. In the Adjust Size window, enter the maximum width under Width: or the maximum height under Height. The other dimension will change automatically to maintain the image's aspect ratio.

4. Make sure that Scale proportionally and Resample image are checked. These options ensure that the image looks good at the reduced size and can be enlarged to a limited degree without losing quality.

What happens if Adjust Size… is grayed out in the menu? If this occurs, it means you're trying to resize an image that has been saved in a format that Preview doesn't allow resizing, such as JPEG. To resolve this issue, export the image to a lossless file format like PNG, resize the copy, and then re-export it to its original format.

To set up a keyboard shortcut for resizing images in Preview, follow these steps:

1. Select Tools | Adjust Size… from the menu.

2. In the Adjust Size window, click on the 'Keyboard' button at the bottom left corner of the screen.

3. Click on the '+' button next to the keyboard shortcut field and enter your desired shortcut (e.g., Command + Shift + R).

4. Click 'Add' to save the shortcut.

Preview supports various image file types that can be resized, including PNG, TIFF, GIF, and BMP. By following these simple steps, you can easily resize images on your Mac using the Preview application.

How to change size of image on mac