How to Resize Photos on Mac: A Comprehensive Guide

When it comes to working with photos on a Mac, a common task is to resize them. Resizing photos can be necessary for various reasons, from making them suitable for email attachments to ensuring they fit into a website’s design. If you’re new to Mac or have never resized a photo before, fret not! In this article, we will guide you through the steps of resizing photos on a Mac using the built-in Preview app.

Steps to Resize a Photo on a Mac

Step 1: Open the Photo in Preview

The first thing to do is open the photo that you want to resize using Preview, Apple’s default image viewer app. To do this, simply double-click the photo file in Finder or right-click on the file and select “Open With” and then “Preview”. The photo will open in a new Preview window.

Step 2: Select the “Adjust Size” Option

Next, select “Adjust Size” from the “Tools” menu in the top toolbar or use the keyboard shortcut “Command” + “Option” + “I”. This will bring up the “Adjust Size” dialog box.

Step 3: Enter the New Dimensions

In the “Adjust Size” dialog box, you’ll see the current dimensions of the photo listed next to “Pixel Dimensions”. To resize the photo, enter the new dimensions you want it to have in the “Width” and “Height” fields. You can select either “pixels”, “inches”, “centimeters”, or “points” as the unit of measurement.

Step 4: Opt for Scale Proportionally

Make sure that the “Scale proportionally” checkbox is selected to ensure that the photo’s aspect ratio is maintained while resizing. This means that the photo won’t appear stretched or distorted after the resizing.

Step 5: Adjust Resolution (Optional)

If you want to change the resolution of the photo (which is the number of pixels per inch), you can adjust it in the “Resolution” field. Keep in mind that this won’t affect the photo’s size in terms of its width and height but can impact its quality when printing.

Step 6: Preview the New Size

After entering the new dimensions, you can click on the “OK” button to see a preview of the resized photo. If you’re satisfied with the result, click “File” > “Save” to save the new image file.

Step 7: Save a Copy

If you want to keep the original photo and have a resized copy, select “File” > “Duplicate” to create a new version of the photo with the new dimensions. You can then save this copy while still keeping the original file untouched.

Step 8: Use the Export Function (Optional)

If you want to export a resized copy of the photo to a specific format or file type, such as JPEG or PNG, you can use the “Export” function. Select “File” > “Export” from the top toolbar and choose the format and quality settings you prefer. This will create a new file with the same dimensions you set in the “Adjust Size” dialog box.

Step 9: Drag and Drop to Resize Multiple Photos

If you need to resize multiple photos at once, you can use the drag and drop method in Preview. Open the original photos in Preview, select them all, and then drag them to the desired folder or location while holding down the “Option” key. This will create resized copies of all the photos with the new dimensions you set in Step 3.

Step 10: Use Third-Party Apps (Optional)

If you prefer using third-party apps to resize photos or need more advanced features than Preview offers, you can consider apps such as Adobe Photoshop, Pixelmator, or GIMP. Keep in mind that these apps usually come with a learning curve and require a subscription or one-time purchase.

Step 11: Back Up Original Photos

Before resizing any photo, it’s always a good idea to back up the original file in case something goes wrong during the resizing process. This can be done by copying the file to a different folder or uploading it to a cloud storage service like Dropbox or Google Drive.

Step 12: Practice and Experiment

Finally, the more you practice resizing photos on a Mac, the more comfortable you’ll become with the process. Don’t be afraid to experiment with different dimensions, resolutions, and quality settings to find the best outcome for your needs.


Resizing photos on a Mac can be a straightforward process thanks to the built-in Preview app. Preview offers basic editing tools that are simple to use even for beginners. When resizing photos, it’s essential to keep in mind the aspect ratio of the image, which is the relationship between its width and height. If you resize a photo without maintaining its aspect ratio, it can look distorted or stretched, which is usually unwanted. If you’re not sure about the new dimensions, you can always preview the resized photo before saving it and adjust the settings accordingly.

Tips and Tricks

1. Use the Keyboard Shortcut

You can use the keyboard shortcut “Command” + “Option” + “I” to open the “Adjust Size” dialog box quickly instead of going through the “Tools” menu.

2. Revert to the Original Size

If you make a mistake while resizing a photo or decide to keep the original dimensions, you can select “Tools” > “Revert to Original” to undo any changes you made.

3. Crop the Photo Before Resizing

If you want to remove unwanted parts of the photo before resizing it, you can use the “Crop” tool in Preview. This can help you avoid resizing too much of the original image when you don’t need to.

4. Use the Preview Thumbnails

In Preview, you can view a thumbnail of the original image and the resized version side by side before saving the new file. This can be helpful in comparing the quality and size of both versions.

5. Batch Rename Resized Copies

When resizing multiple photos using Preview, you can select them all and then select “File” > “Export Selected Images” to export all the photos with the same dimensions and file format. You can also add a custom prefix or suffix to the filenames to differentiate them from the original files.

6. Use Third-Party Apps for Advanced Resizing

If you need to resize photos for professional or creative purposes, using third-party apps like Photoshop or Pixelmator can provide you with more advanced features and precision control over the resizing process.

7. Keep the Original File Format

If you’re not sure which file format to choose when saving the resized photo, it’s best to keep the original file format to maintain the quality of the image.

8. Experiment with Different Resolutions

Depending on the purpose of the resized photo, different resolutions can have a significant impact on its quality. For example, a lower resolution may be suitable for web use, while a higher resolution may be needed for printing.

9. Use Shortcut for Duplicate

You can use the shortcut “Command” + “D” to quickly duplicate a photo before resizing it. This can save you time in selecting “File” > “Duplicate”.

10. Avoid Over-Resizing

While it may be tempting to resize a photo to a much larger size than its original dimensions, keep in mind that this can lead to a loss of quality and cause the photo to appear pixelated or blurry.

Advantages and Disadvantages of Resizing Photos on a Mac

The Advantages of Resizing Photos on a Mac

1. Convenience: Resizing photos on a Mac is extremely convenient because you don’t need to download any third-party software. The default Preview app that comes with your Mac is all you need.

2. Simplicity: The process of resizing photos on a Mac is simple and straightforward. Anyone can do it!

3. Quick: It only takes a few seconds to resize a photo on a Mac, which is handy when you need to resize a large number of photos.

4. Free: You don’t have to spend any money to resize photos on a Mac.

5. Customization: You can choose to resize photos to any size you want, making it easy to fit them into specific projects or to share them on the internet.

6. Easy Sharing: Resizing photos on a Mac makes it easier to share them on various social media platforms.

7. Saves Space: Resizing photos on a Mac can save a lot of storage space on your device, especially if you have a large number of high-resolution photos.

8. High-Quality: When you resize photos on a Mac, you maintain the image’s quality, unlike other resizing tools that tend to reduce the quality of the image.

9. Better Performance: By resizing photos on a Mac, you can improve the performance of your device by reducing the file size of the images.

10. Time-Saving: Resizing multiple photos at once on a Mac can save you a lot of valuable time.

The Disadvantages of Resizing Photos on a Mac

1. Limited Features: Resizing photos on a Mac provides few to no editing options beyond resizing.

2. Only for Mac Users: If you don’t have a Mac, you can’t use the built-in Preview app to resize photos.

3. Less Control: Other resizing software may give more control over the outputted image file, the size, and other options.

4. Can Be Confusing: The preview app has a range of features and may be generally confusing for first-time users.

5. Lesser Options: Preview app can only convert pictures to basic types E.g., jpeg, png.

6. Cannot Change DPI: The Preview app in macOS cannot change pixel densities for images like PC image software.

7. Losing Some Details: When you resize photos on a Mac, especially when reducing their size, you may lose some of their details, which can be a significant disadvantage for photographers and designers who require high-quality images.

8. No Watermarking: Unlike other third-party resizing tools, the default preview app on your Mac does not support watermarking.

9. Can’t Resize PDFs: Preview can’t resize PDF files, and you’d want to use another app for that.

10. Can’t Resize Multiple Folders: Preview only handles images that are in the same folder, and you’d have to work on multiple folders individually.


1. How can I resize a photo on my Mac?

You can resize a photo on your Mac by using the built-in Preview app. Simply open the image in Preview, select “Tools” from the top menu bar, and click on “Adjust Size”. Here, you can set the desired dimensions for your image and save the file.

2. Is it possible to resize multiple photos at once?

Yes, it is possible to resize multiple photos at once on your Mac using Preview. Simply select all of the images you want to resize, right-click, and choose “Open With Preview”. Then follow the same steps as above to adjust the size of the images.

3. What is the recommended image size for social media profiles?

The recommended image size for social media profiles varies depending on the platform. For example, the current profile picture size for Facebook is 180 x 180 pixels, while for Instagram it is 110 x 110 pixels. It’s best to check each platform’s guidelines for specific recommendations.

4. Can I resize an image without losing quality?

Resizing an image may result in some loss of quality, but there are ways to minimize this. When resizing in Preview, make sure to check the box for “Scale proportionally” to maintain the aspect ratio. You can also choose the “Best” option for the interpolation method to improve the quality of the resized image.

5. How do I crop an image on my Mac?

You can easily crop an image on your Mac using the Preview app. Simply select the portion of the image you want to keep, click on “Tools” in the top menu bar, and choose “Crop”. Then save the new, cropped image.

6. Is it possible to resize an image using keyboard shortcuts?

Unfortunately, there are no built-in keyboard shortcuts for resizing images in Preview. However, you can create your own custom keyboard shortcut using the “Keyboard” settings in System Preferences.

7. Can I resize an image using third-party apps?

Yes, there are many third-party apps available for resizing images on your Mac. Some popular options include Adobe Photoshop, Pixelmator, and GIMP.

8. How do I resize an image for printing?

When resizing an image for printing, it’s important to make sure the resolution is high enough to ensure quality. A good rule of thumb is to have a resolution of 300 pixels per inch (PPI) for printing. To adjust the size, follow the same steps as above in Preview or another image editing app.

9. Can I resize images in bulk using a third-party app?

Yes, many third-party apps offer bulk image resizing functionality. Some popular options include ImageResize, Resize Me! Pro, and BatchPhoto.

10. How do I resize an image using the command line?

You can resize an image using the command line on your Mac by using the sips (Scriptable Image Processing System) command. Simply open Terminal and enter the command “sips -Z [desired width] [image file name]”. Replace [desired width] with the desired pixel width and [image file name] with the file name of the image you want to resize.

11. Can I resize images without an app?

Yes, you can resize images without an app by using various online tools such as PicResize, Bulk Resize Photos, or ResizePixel. However, keep in mind that uploading images to third-party sites can pose security risks, so it’s best to use trusted sites and exercise caution when sharing personal information.

12. How do I resize an image in Pages or Keynote?

You can resize an image in Pages or Keynote by selecting the image, clicking on the “Format” button in the top menu bar, and choosing “Image”. Here, you can adjust the size of the image and choose how it’s scaled.

13. Can I resize images on my iPhone or iPad?

Yes, you can easily resize images on your iPhone or iPad using the Photos app. Simply select the photo you want to resize, tap “Edit”, then select “Crop & Rotate” and adjust the dimensions as desired.

How to Resize Photo on Mac

Are you looking for a way to resize your photos on your Mac computer? Look no further, as we have compiled an easy-to-follow guide for you to do just that.

The first step to resizing your photo on a Mac is to open the photo you wish to resize. You can do this by double-clicking on the photo or dragging it into Preview, the default image viewer on Mac computers.

Once the photo is open, go to the “Tools” menu and select “Adjust Size.” A dialogue box will appear with the current dimensions of the photo. You can either adjust the dimensions manually by entering new values or by selecting a preset size.

It is important to note that changing the dimensions of a photo can affect its overall quality. To avoid losing quality, make sure to select the “Scale proportionally” box to maintain the aspect ratio of the photo.

Conclusion and Closing

There you have it, a simple way to resize your photos on a Mac without the need for additional software. Remember to always maintain the aspect ratio of the photo to avoid distortion and loss of quality.

We hope you found this guide helpful. Thank you for reading and best of luck with your photo resizing endeavors. Until next time!