Need to scale down a massive image file? Here’s how to do it in seconds

This article was updated on 5-19-2017 by Tyler Lacoma to include instructions for Paint and Resizer.

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 five tools that allow you to do so, including those for both 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, GIMP, and Preview

Photoshop — Windows and MacOS

Photoshop is a fantastic tool for resizing an image if you already have Adobe’s flagship software buried within your image-editing arsenal. Read on to find out how to use it for resizing 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.

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 — Windows and MacOS

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.

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.

Step 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 — MacOS

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.

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.