How to Resize an Image on Windows and Mac

Published August 12, 2026

Resizing a photo shouldn't need a subscription or a 2 GB download. Whatever device you're on right now already has something that can do it — you just have to know where it's hidden. This guide covers the built-in method on Windows 11, macOS, iPhone and Android, explains where each one falls short, and shows the browser method that works identically on all four and handles whole folders at once.

One thing to settle before you start: resizing changes how many pixels the picture has. Cropping cuts parts of it away. If your goal is "make this file smaller" or "fit this into 1200 pixels wide", resizing is what you want.

Windows: resize in Paint

Paint has shipped with every version of Windows for forty years and still does the job.

1. Right-click your image → Open with → Paint.
2. Click Resize in the toolbar (in Windows 11 it's the icon with two arrows; in Windows 10, Resize and skew).
3. Switch from Percentage to Pixels.
4. Make sure Maintain aspect ratio is ticked, then type the width you want. The height fills in automatically.
5. Click OK, then File → Save as and give it a new name so your original survives.

Where it falls short: one image at a time, and Paint re-saves JPGs at a fixed quality you can't control. Fine for a single photo, painful for twenty.

Windows: the Photos app alternative

The Windows Photos app also has a resizer — open the image, click the … menu and choose Resize image. It offers preset sizes plus a custom option and shows an estimated file size, which is handy when you're chasing an upload limit. It still handles only one file at a time.

Windows: resizing several at once

For a folder of photos, select them all in File Explorer, right-click and look for Resize pictures — it appears if you have Microsoft PowerToys installed, which is a free official download. Without PowerToys, Windows has no built-in batch resizer, and that's exactly where a browser tool saves you the install.

Mac: resize in Preview

macOS has the better built-in answer. Preview handles batches natively and gives you a live file-size estimate.

1. Double-click the image to open it in Preview (or right-click → Open With → Preview).
2. Choose Tools → Adjust Size from the menu bar.
3. Set the units to pixels, tick Scale proportionally, and enter your target width.
4. Watch the Resulting Size readout at the bottom — that's your new file weight.
5. Press OK, then File → Export to save a copy (Export also lets you pick format and quality; plain Save overwrites the original).

For a batch: select every photo in Finder, press the space bar or open them all in one Preview window, hit Cmd+A in the sidebar to select all thumbnails, then run Tools → Adjust Size once. Every selected image is resized together.

Where it falls short: it's easy to overwrite your originals by accident, and the Quick Actions route (right-click → Quick Actions → Convert Image) only offers Small / Medium / Large rather than a specific number.

iPhone: there's no real resizer

This surprises people, but iOS Photos has no resize function — the editor only crops, which changes the shape, not the resolution. Your options are:

• Mail's built-in shrink: attach the photo to an email and iOS offers Small / Medium / Large / Actual Size. Crude but instant, and the email version is genuinely smaller.
• The Files app: long-press an image, choose Quick Actions, and you'll find limited size presets.
• A browser resizer: open the tool in Safari, tap to pick a photo from your library, set the size, and the file saves back to Downloads or Photos. This is the only way to hit an exact pixel width on iOS without installing anything.

A useful related tip: iPhones save photos as HEIC by default, which many sites reject. If you hit that wall, convert HEIC to JPG first, then resize.

Android: it depends on your phone

Android has no single answer because every manufacturer ships a different gallery app. Samsung's Gallery has Resize image tucked in the editor's more-options menu; Google Photos does not have one at all, only crop. Rather than hunting through your particular skin's menus, opening a browser resizer in Chrome works identically on every Android phone and every Android version.

The method that works everywhere: your browser

A browser-based resizer sidesteps the whole problem. There's nothing to install, it behaves the same on a work laptop and a phone, and it handles batches that Paint and Photos can't.

1. Open the Toolyard Image Resizer in any browser.
2. Drag your photos onto the box — one, or fifty. On a phone, tap to choose from your camera roll.
3. Pick Percentage to scale everything down by a factor, or Max width & height to fit every image inside a box such as 1600×1600. Aspect ratio is kept automatically, so nothing gets stretched.
4. Optionally set the Output format — JPG for compatibility, WebP for the smallest files, PNG to keep transparency.
5. Click Download on a single image, or Download all to save the whole set.

The max-box mode is the one that saves the most time on a mixed folder: portrait and landscape photos both come out correctly without you sorting them first, and nothing ends up larger than your limit in either direction.

Which method should you use?

One photo, already at your desk on Windows: Paint is fine, and it's two clicks away. One photo on a Mac: Preview, because the live file-size readout tells you when you've hit an upload limit. A folder of photos, any platform: the browser resizer, unless you already have PowerToys or are comfortable with Preview's multi-select. On a phone: the browser, because neither iOS nor Android offers a proper resizer. An exact pixel size the built-in tools can't hit: crop to the target ratio first, then resize.

Three things worth doing whatever you use

Keep the original. Always save the resized version as a new file. Pixels you delete are gone for good — enlarging back later produces a soft, mushy image because there's no detail to restore.

Don't resize a resized file. Each JPG re-save discards a little more detail permanently. Go back to the master and resize once to your final size.

Resize before you compress. If you're chasing a file-size limit, shrinking dimensions usually gets you there alone — halving the width cuts about 75% of the file. Only reach for a compressor if you're still over after resizing.

Is it private and free?

Yes. The Toolyard resizer runs entirely inside your browser — your photos are read, resized and saved on your own device using the HTML Canvas, and are never uploaded to any server. No account, no watermark, no limit on how many files you run through. Once the page has loaded you can turn your Wi-Fi off and it still works, which is the simplest possible proof that nothing is being sent anywhere.