Image tool
Image Resizer
Resize an image to the exact pixel dimensions you need, or scale it by a percentage, all in your browser. Lock the aspect ratio to keep the image from stretching, preview the new dimensions, and download the result.
Your image is processed locally — nothing is uploaded.
Privacy & data handling
Browser processingThis tool processes your input locally in your browser. Nothing is uploaded to a server or sent to an external service.
Interactive tool
Image Resizer
Choose files to process
Overview
What does Image Resizer do?
This tool resizes an image using one of two modes. Percentage mode scales the image by a set amount (25%, 50%, 100%, or a custom value). Exact dimensions mode sets the width and height in pixels.
An aspect-ratio lock keeps proportions intact: change the width and the height adjusts automatically, so subjects don't get squashed or stretched. Turn the lock off to set width and height independently.
The tool shows the original and new dimensions with the calculated scale, and previews the result before you download it.
Under the hood
How does it work?
Your image is decoded and drawn onto a canvas at the target dimensions. The browser's image smoothing interpolates pixels when scaling — this keeps downscaling clean and sharp, and makes upscaling smooth rather than blocky.
The tool calculates the new dimensions live as you adjust the controls: percentage mode multiplies the original size by the chosen percent, and dimensions mode uses the values you enter, with the aspect-ratio lock keeping them proportional.
The resized image is encoded and offered as a download with the original format preserved.
Key features
Features of Image Resizer
Use cases
When should you use Image Resizer?
Social media dimensions
Resize a photo to a platform's preferred size — a 1200×630 share card, a 1080×1080 square post — before uploading.
Website images
Fit images to a template's exact slot dimensions so layouts never shift while loading.
Email signatures and thumbnails
Produce small, consistent images for email signatures, avatars, and product thumbnails.
Preparing uploads
Match an upload portal's required dimensions exactly to avoid automatic (and ugly) cropping.
Step-by-step
How to use Image Resizer
- Step 1
Upload your image.
- Step 2
Enter the desired width and height in pixels.
- Step 3
Download your resized image.
Real example
Example
Before
holiday-photo.jpg 4000 × 3000 px 6.1 MB
After (1200 × 900, aspect locked)
holiday-photo-resized.jpg 1200 × 900 px ~700 KB
Illustrative. Downscaling keeps visual quality; file size drops because there are simply fewer pixels.
Technical information
How the details work
Resizing re-samples the image: the browser reads the source pixels and computes new pixel values for the target grid. Downscaling averages groups of pixels together, which naturally sharpens and reduces file size — a 4000px photo resized to 1200px is dramatically smaller with little visible quality loss.
Upscaling is the opposite: new pixels are interpolated between existing ones, which increases size but cannot add real detail. If you need to enlarge an image, it is usually better to start from a high-resolution source than to upscale a small file.
The aspect-ratio lock matters because setting width and height independently without it distorts the image — the browser simply stretches the pixels. The lock keeps the ratio constant and prevents that.
Privacy & security
Your data stays yours
Your image is resized entirely in your browser with the canvas API. It is never uploaded or stored.
Local processing — files stay in your browser
- The image is decoded and resized locally — no copy leaves your device.
- The resized file is generated locally and downloaded directly.
- Nothing is retained after you close the tab.
- Analytics only record the page visit.
Limitations
What this tool does not do
- Upscaling cannot add detail — enlarged images may look soft (use the Image Upscaler workflow for larger outputs).
- Each image is processed individually; batch resizing is not available.
- Very large images may exceed browser canvas limits.
- Setting width and height independently without the aspect lock will distort the image.
Frequently asked questions
Common questions about Image Resizer
Does resizing reduce quality?
Downscaling (making an image smaller) keeps visual quality and reduces file size. Upscaling interpolates new pixels and can look soft, since no new detail is created — that is why the tool preserves the aspect ratio rather than stretching.
What is the aspect ratio lock for?
It keeps width and height proportional. When it is on, changing the width automatically adjusts the height so subjects are never squashed or stretched. Turn it off only when you intentionally want a non-proportional size.
Can I resize multiple images at once?
Currently each image is processed individually. Batch resizing is not available in this version.
What formats are supported?
JPG, PNG, and WebP images can be resized, and the output keeps the original format. Transparency in PNG and WebP sources is preserved.
Can I resize very large images?
There is no server-side limit, but very large images can exceed the browser's canvas limits. If a browser cannot handle an image, the tool reports it.
Are my images safe to resize here?
Yes. Resizing happens locally in your browser and your image is never uploaded.
What is the difference between percentage scaling and exact pixel resizing?
Percentage scaling changes width and height uniformly relative to original dimensions (e.g. 50% reduces both dimensions by half). Exact pixel resizing lets you specify target dimensions (e.g. 1200x630 for social sharing).
Does resizing down reduce the file size automatically?
Yes. Downscaling reduces the total pixel count. For example, resizing a 4000x3000 photo (12 megapixels) to 1200x900 (1.08 megapixels) eliminates over 90% of the raw pixel data, drastically cutting file size.
Why do downscaled screenshots with small text sometimes look blurry?
Downscaling sub-pixel text averages neighboring high-contrast pixels together. For crisp screenshots with tiny code or text, crop the area of interest rather than aggressively downscaling the entire screen.
How does the aspect ratio lock work?
When enabled, changing width automatically recalculates height = width * (originalHeight / originalWidth), preventing stretching or squishing distortion.
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Related guides
Practical articles to help you get the most out of this tool and related workflows.
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How to Compress Images Without Losing Visible Quality
Practical techniques for reducing image file size while keeping photos and graphics looking sharp.
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How to Resize Images Without Losing Quality
Resize photos and graphics to exact pixel dimensions or a percentage — and keep them sharp for web, print, and uploads.
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