Image Resizer

Resize images online for free. Change dimensions of PNG, JPG, and WebP files while maintaining quality. No upload required - works in your browser.

Input

Supported formats: PNG, JPG, WebP

Resize your images quickly and securely without uploading them to a server. Adjust width and height while maintaining aspect ratio.

What is the Image Resizer?

The Image Resizer is a browser-based tool that allows you to change the dimensions of your images. Whether you need to shrink a photo for a website, create a thumbnail, or adjust an image for social media, this tool makes it easy. It supports common formats like PNG, JPEG, and WebP.

How the image resizer works

Your file never leaves the page: a FileReader turns it into a data: URL that an off-screen Image element decodes. Leave both boxes empty and the original dimensions are kept. With "maintain aspect ratio" on, a missing side is derived from the source ratio and rounded to a whole pixel; supply both and they are treated as a bounding box — the side that would overflow shrinks, so nothing is cropped or stretched. The pixels are redrawn into a canvas with high-quality smoothing, then encoded by toDataURL at quality 0.9, which JPEG and WebP honour and lossless PNG ignores. Choosing JPEG flattens transparency to black.

Key Features

Client-side processing: Your images never leave your browser.
Support for PNG, JPEG, and WebP formats.
Maintain aspect ratio option.
Real-time preview of the resized image.
Fast and secure.

How to Use

1

Select an image file from your device.

2

Enter your desired width or height.

3

Check 'Maintain Aspect Ratio' to automatically calculate the other dimension.

4

Select the output format (PNG, JPEG, or WebP).

5

Click 'Run Tool' to resize the image.

6

Download the resized image from the preview section.

Common Mistakes

Upscaling small images too much, which causes pixelation.
Forgetting to maintain aspect ratio, resulting in stretched images.
Choosing the wrong format (e.g., using JPEG for transparent images).

Use Cases

Resizing photos for email attachments.
Creating thumbnails for YouTube or blog posts.
Optimizing images for faster website loading.
Adjusting profile pictures for social media.

See also

  • Base64 Image Encoder — Once the image is down to the right dimensions, turn it into a data: URI you can paste straight into CSS or HTML.
  • Favicon Downloader — Useful when you need the icon sizes a site already ships before deciding which square dimensions to resize your own artwork to.

FAQ

Is it free?

Yes, this tool is 100% free to use.

Are my images uploaded?

No, all processing happens locally in your browser. Your images are not sent to any server.

What formats are supported?

We support PNG, JPEG, and WebP.