Image Resizing

How to Resize an Image

Your image is the wrong size for an upload form, email, or document. Here's how to resize it on any device — browser, Windows, Mac, iPhone, or Android — without installing anything extra.

Method 1 — Browser tool (fastest, any device)

Works on any device, any operating system, any browser. Drop your image, enter the target dimensions or percentage, download. Under 15 seconds. Nothing is uploaded to a server.

Image ResizerUse it →

Method 2 — Windows (built-in Paint)

1Open the image in Paint (search 'Paint' in the Start menu).
2Click Home → Resize in the toolbar.
3Choose 'Pixels', uncheck 'Maintain aspect ratio' if needed, enter your target Width and Height.
4Click OK, then File → Save As → choose your format (JPEG Picture or PNG Picture).

Paint saves at a fixed quality level. For more control over output quality, use the browser method above.

Method 3 — Mac (built-in Preview)

1Open the image in Preview (double-click the file, or right-click → Open with → Preview).
2Go to Tools → Adjust Size in the menu bar.
3Enter your target Width or Height. Check 'Scale proportionally' to keep the aspect ratio.
4Click OK, then File → Export → choose format and quality → Save.

Method 4 — iPhone and Android

Neither iOS nor Android have a built-in image resizer that lets you set exact pixel dimensions. The browser method is the most reliable: open the resizer tool in Safari (iOS) or Chrome (Android), upload your image, enter the dimensions, download.

On iPhone, you can also use the Shortcuts app — it has a built-in “Resize Image” action that can be added to a shortcut and triggered from the share sheet. This is useful if you resize images often and want a one-tap workflow.

Resize vs crop — which do you need?

Resize
You want to make the whole image smaller or larger while keeping all the content visible.
Crop
You want to cut away parts of the image and keep only a specific area — useful for changing aspect ratio without stretching.

Need to crop? Use the Crop Image tool →

Frequently asked questions

How do I resize an image online for free?

Use a browser-based image resizer — open the tool, drop your image, set the width and height (or a percentage), and download the resized file. No installation, no account. The resize happens in your browser so your file is never uploaded to a server.

How do I resize an image in Windows?

Open the image in Paint, then go to Home → Resize. You can resize by percentage or by pixels. Uncheck 'Maintain aspect ratio' if you want to set width and height independently. Click OK, then File → Save As to save the resized image. For more control (quality settings, format choice), use a browser-based resizer.

How do I resize an image on a Mac?

Open the image in Preview (macOS's built-in viewer). Go to Tools → Adjust Size. Enter your target width or height — tick 'Scale proportionally' to keep the aspect ratio. Click OK, then File → Export to save in your preferred format and quality. Preview is free and already on every Mac.

How do I resize an image on iPhone?

iOS doesn't have a built-in image resizer, but a browser-based tool works in Safari. Open the resizer, tap to upload from Photos or Files, set the dimensions, and save the result to your device. For frequent resizing, the Shortcuts app can automate this with a 'Resize Image' action — no external app needed.

How do I resize an image on Android?

Open a browser-based image resizer in Chrome, upload your image, set the target dimensions, and download. The file saves to your Downloads folder. Alternatively, Google Photos has a basic export option, though it doesn't offer exact pixel dimension control. A browser-based tool gives you the most precise control.

What's the difference between resizing and cropping an image?

Resizing changes the pixel dimensions of the entire image — the full image content gets smaller or larger. Cropping removes parts of the image — you cut away the edges or sides, keeping only a selected area at its original (or rescaled) resolution. Both change the output dimensions, but resizing keeps all content while cropping removes some.

More from QuickToolsHub: Image Resizer · Crop Image · Image Compressor