How to Resize an Image on Windows, Mac, iPhone, and Android (2026)

You need to resize an image: maybe it’s too large to email, it’s crashing a website upload form, or it’s inflating a PowerPoint file. It’s worth a look at the built-in tools already on Windows, macOS, iPhone, and Android before you download anything.

Resize an Image on Windows

Paint is the quickest built-in option on Windows 10 and 11. It actually works better than you might expect for something that ships free with every copy of Windows. For more control over quality and resolution, GIMP is a free download with professional-grade options.

Method 1: Use Paint (Windows 10 and 11)

1. Open File Explorer, right-click your image, and select Open with > Paint.

2. In the Home tab of the ribbon, click Resize.

3. In the Resize and Skew dialog, select Pixels. Type your target width in the Horizontal field. Leave Maintain aspect ratio checked; the height updates automatically so you don’t accidentally distort the image.

4. Click OK. Press Ctrl + S to overwrite the original, or go to File > Save as to keep both versions.

Method 2: Use GIMP (free download)

GIMP gives you precise control over interpolation method and output resolution, a clever option when sharpness matters or you’re exporting for print. Download the current version free at gimp.org.

1. Open GIMP, then go to File > Open and select your image.

2. Click Image in the menu bar and select Scale Image.

3. Enter your target Width in pixels. The chain-link icon between the Width and Height fields locks the aspect ratio; leave it linked so height adjusts automatically. If it appears broken, click it to re-link.

4. Leave Interpolation set to Cubic for the smoothest result, then click Scale.

5. Go to File > Export As to save the resized image as JPG or PNG. File > Save only writes GIMP’s native .xcf format; always use Export As to finish.

Resize an Image on macOS

macOS ships with Preview, which handles resizing smoothly without any third-party software. For batch jobs across a whole folder of photos, the built-in Quick Actions feature handles dozens at once without opening a single app.

Method 1: Use Preview

1. In Finder, right-click your image and choose Open With > Preview.

2. Click Tools in the menu bar, then select Adjust Size.

3. In the dialog, enter your new Width in pixels. Make sure Scale proportionally is checked; the height updates automatically to preserve the aspect ratio.

4. Click OK. Go to File > Export to save a resized copy, or press Command + S to overwrite the original.

The dialog shows you the resulting file size before you commit, which is a nice touch for hitting email attachment limits or upload caps without guessing.

Method 2: Batch resize with Quick Actions

If you need to resize an entire folder of photos at once, Finder’s Quick Actions can handle it without opening any app.

1. In Finder, select all the images you want to resize. Hold Command and click to pick individual files, or press Command + A to select everything in the folder.

2. Right-click the selection and choose Quick Actions > Convert Image.

3. In the Convert Image sheet, choose your output format (JPEG, PNG, or HEIF), then click the size dropdown and select Small, Medium, Large, or Actual Size.

4. Click Convert to [Format]. macOS saves the resized copies to the same folder and leaves your originals untouched.

Resize an Image on iPhone or iPad

iOS 18’s built-in Photos app handles cropping to standard aspect ratios quickly, but for resizing to an exact pixel dimension, the free Image Size app from the App Store is the right pick.

Method 1: Crop to a ratio using Photos (no install needed)

1. Open the Photos app and tap the photo you want to resize.

2. Tap Edit in the top-right corner.

3. Tap the crop and rotate icon in the editing toolbar at the bottom of the screen.

4. Tap the aspect ratio button (a rectangle icon in the top-right of the crop view) to open the ratio picker. Choose from presets like Square, 4:3, 16:9, or Free.

5. Adjust your crop frame, then tap Done. The edit saves over the original. Tap Revert at any time to restore the full-resolution photo.

This works great for social media crops. If you need to hit a specific pixel count, like 1200×630 for a blog header, use Image Size below.

Method 2: Resize to exact dimensions using Image Size

1. Download the free Image Size app from the App Store.

2. Open Image Size and tap the photo icon to import an image from your Photos library.

3. Tap the width field and type your target pixel width. The aspect ratio lock is on by default, so height adjusts automatically.

4. Tap Save Image to export the resized photo back to your Photos library.

Resize an Image on Android

Android’s resize options vary by manufacturer. Samsung, Google Pixel, and others each ship their own Gallery or Photos app with different menu layouts. The steps below follow the most common pattern, but your menus may look slightly different depending on your device.

Resize using your Gallery or Photos app

1. Open the Gallery or Photos app and tap the image you want to resize.

2. Tap Edit (a pencil icon or three-dot menu, depending on your device).

3. Look for a Resize or Image Size option in the editing toolbar. On Samsung devices, go to Edit > More > Resize. On Google Pixel, the built-in Photos app doesn’t include a resize option. Skip to the app recommendation below.

4. Choose a percentage of the original (75%, 50%, or 25%) or enter specific dimensions if your app supports them.

5. Tap Save copy to preserve your original at full resolution alongside the resized version.

If your Android gallery app doesn’t include a resize option, the free Photo & Picture Resizer on the Play Store covers it reliably across all devices.

Conclusion

For most one-off jobs, Paint on Windows and Preview on macOS are genuine gems: built-in, accurate, and done in under a minute. If you’re resizing batches of photos regularly, the macOS Quick Actions method is worth bookmarking: it processes a whole folder at once with no manual steps. On iPhone, the free Image Size app fills the gap that Photos won’t. It’s the one worth spreading the word about. You can also learn more about rotating a picture in Microsoft Word or explore other image editing tools like Microsoft Paint for more advanced tasks.