Resizing an image doesn’t have to be rocket science. It’s true that more robust image-editing software sports all sorts of magical functions — i.e., content-aware analysis and 3D rendering, among other highlights — but resizing an image is as basic as it gets.

Almost all, if not all, image editing software contains easily-accessible resizing tools that can resize your image to your desired proportions, whether it be in pixels, inches, or by a specified percentage change. Below, we’ve outlined how to resize an image using five tools for Windows and MacOS. Also, check out our picks for the best free image-editing tools, if you’re looking for some capable programs without having to resort to your savings fund.

Note: Although it is generally fine to shrink an image, enlarging an image often results in quality degradation, reducing the image’s crispness and visual fidelity. Just keep that in mind when re-sizing.

Photoshop

Photoshop is a fantastic tool for resizing an image if you already have Adobe’s flagship software buried within your image-editing arsenal.

It’s not the most lightweight or inexpensive image editor, but it works for both MacOS and Windows 10 and is quite comprehensive. Here’s how to use it to resize images.

Step 1: Launch Photoshop and open your image

Launch whatever version of Photoshop you have installed and open the image you’d like to resize. To do so, click File in the Photoshop top menu and choose Open from the resulting drop-down menu. Afterward, select your image from its save location and click the Open button in the bottom-right corner.

how to resize an image photoshop

Step 2: Resize your image

Once you’ve opened the image, click Image in the Photoshop top menu and choose Image Size from the resulting drop-down menu. A small pop-up window will appear housing various options for resizing and altering your image to your preferred specifications.

Select your desired width and height — either by specifying the dimensions in pixels or percentage — and make sure the “Constrain Proportions” and “Resample image” boxes are checked. This will ensure you maintain the proper proportions when rescaling your image. When finished, click the OK button in the upper corner of the window.

GIMP

how to make a video game gimp1

GIMP, aka GNU Image Manipulation Program, is the Wikipedia of image-editing software; it’s an open-source application that is fueled by a community of volunteers hellbent on making the freemium application a high-quality rival to the many more robust software suites available on the web.

It’s a powerful tool that touts basic and more advanced features alike, albeit with a high learning curve akin to Photoshop and other similar software. It’s an alternative to Photoshop that works for both MacOS and Windows 10.

Step 1: Download and launch GIMP. 

Head to the GIMP homepage and click the orange Download button in the upper-right corner to download the executable file. Once finished, run the necessary installation software before launching the program by navigating to your main application or program folder and clicking the GIMP icon. When installing the application, remain wary of any additional add-ons, toolbars, or general malware that may come bundled with the software.

Step 2: Open your image.

Once open, click File in the GIMP top menu and choose Open from the resulting drop-down menu. Then, select your image from its save location and click the Open button in the bottom-right corner.

GIMP EditorStep 3: Resize your image.

Once the image is opened, click Image in the GIMP top menu and choose Scale Image from the resulting drop-down menu. A small pop-up window will appear housing various options for resizing and altering your image to your preferred specifications. Select your desired width and height by specifying the dimensions in pixels, inches, or picas, among other options, and click the Scale button at the bottom of the window.

Preview

There’s a reason Preview has come pre-installed on all versions of MacOS for more than a decade. The built-in application is a fantastic, lightweight tool for making basic photo edits and adjustments, in lieu of more intensive software like Photoshop.

Preview is typically set as the default program for viewing images and PDFs, hence it’s usually the first program to open your newly-imported images and doesn’t require any external software.

Step 1: Launch Preview and open your image.

Click the Preview icon depicting two photos and a magnifying glass in the main applications folder to launch the program. Once open, click File in the Preview top menu and choose Open from the resulting drop-down menu. Next, select your image from its save location and click the Open button in the bottom-right corner.

how to resize an image macos preview

Step 2: Resize your image.

Once you’ve opened the image, click Tools in the Preview top menu and choose Adjust Size from the resulting drop-down menu. A small pop-up window housing various options for resizing and altering your image to your preferred specifications will appear.

Choose from the custom presets at the top or select your desired width and height — either by specifying the dimensions in pixels, inches, centimeters, or percentage, among a host of other options — and make sure the “Scale proportionality” and “Resample image” boxes are checked, as to maintain the proper proportions when rescaling your image. When finished, click the OK button in the upper-right corner.

Paint

Resizing images in the latest iteration of Windows 10 is easy, especially in comparison to earlier versions of the OS. This is because Microsoft chose to remove the Photo Gallery option and focus primarily on using Paint, at least of quick fixes and alterations.

Step 1: Open up Paint.

The easiest way to launch Paint is probably to look for it using the Search box, which is located directly below the Start menu. Click the application’s icon once found — it resembles a paint brush and pallet.

Step 2: Open your image.

Once open, click File in the Paint top menu and choose Open from the resulting drop-down menu. Afterward, select your image from its save location and click the Open button in the bottom-right corner.

Step 3: Move over to the Home tab.

In the Home tab, right beside the Select option, you will see a small tool that says Resize. Select this option to open the Resize and Skew window.

Step 4: Make your adjustments.

The Windows 10 version of Paint allows you to adjust by either pixels or percentages. You can also skew the image when resizing, but if all you want to do is change the dimensions, we don’t recommend that. Make sure “Maintain aspect ratio” is selected, assuming you want the picture to maintain the same general shape, and select OK at the bottom of the window when finished.

Pixlr

Pixlr, a cloud-based set of image-editing software, has made a lasting impression on us since its 2008 debut. The simple suite of apps offers many of the same basic functions you would find in Photoshop, such as image cropping and resizing, but requires no external software and leaves no footprint as it works entirely within your web browser.

Obviously, an active internet connection is your ball-and-chain, but it’s a powerful tool for resizing images according to pixel dimensions if you don’t mind being tethered to the web.

Step 1: Launch Pixlr in your browser and open your image.

Head to the Pixlr editor page and select File then Open Image from the menu. Then, select your image from its save location and click the Open button in the bottom-right corner.

Step 2: Resize your image.

Once the image is opened, click Image in the menu, followed by Image size. A small pop-up window will appear housing various options for resizing and altering your image to your preferred pixel specifications. Select your desired width and height and make sure the “Constrain proportions” box is checked, as to maintain the proper proportions when rescaling your image. When finished, click the OK button.

Simple Image Resizer

Are you in a hurry? Maybe you’re using someone else’s computer or a mobile device, and you don’t want to bring up any of the aforementioned programs. Or perhaps you just want something easier to handle, where you don’t have to run proportions through your head to make sure the image turns out correctly.

Welcome to the web iteration of Simple Image Resizer, a freemium tool that’s also available as an extension for Google Chrome.

Simple Image Resizer

Step 1: Launch the web app and open your image.

Navigate to the Simple Image Resizer website, and click the blue Select Image button in the upper-right corner. Then, select your image from its save location and click the Open button in the bottom-right corner.

Step 2: Define the size of your new image.

Use the slider at the bottom of the web app to select your desired percentage increase. Alternatively, click the bubble beside dimensions and input your desired proportions in the resulting boxes.

Step 3: Resize your image.

Click the green Resize button in the lower-right corner, followed by the Download link on the resulting page. Then, right-click the image, select Save image as…, and rename your image before saving it in a location of your own choosing. That’s it!

Updated on December 4, 2017 by Mark Coppock with refreshed copy.