Resize Images Online

Resize images by pixels or percentage with fit, fill and exact modes — one image or many at once.

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How to use Image Resizer

Upload one or more images.
Pick a resize mode and enter the target width, height or percentage.
Choose an output format and quality.
Batch several files and download them together as a ZIP.

About this tool

The Image Resizer changes image dimensions by pixels or percentage, with Fit, Fill and exact modes. It keeps the aspect ratio by default and never pretends that enlarging a small image adds real detail.

Recommended settings

Fit keeps the whole image inside a box; Fill covers the box and may crop.
Leave “Allow enlarging” off to avoid soft, upscaled results.

Supported formats

Input: JPEG, PNG, WEBP, AVIF, GIF, BMP. Output: JPEG, PNG, WEBP.

Quality & file size

Lossy formats (JPEG, WebP, AVIF) trade detail for smaller files as you lower the quality; PNG stays lossless regardless of the slider. The tool always shows the original and result sizes so you can judge the trade-off, and it never recommends a result that is larger than your original as an “optimisation”.

Privacy

Every image is decoded, transformed and re-encoded entirely in your browser using the Canvas API and a Web Worker. Files are never uploaded, are not stored in localStorage, and are cleared from memory when you remove them or close the page.

Common issues & limitations

Upscaling cannot create detail that is not in the source.
Fill mode centre-crops to reach the exact dimensions.
All processing happens on your device; nothing is uploaded, so very large batches are limited by your available memory.

Frequently asked questions

Does the tool keep the aspect ratio?

Yes, by default. You can unlock it to stretch to exact dimensions, or use Fit to stay within a box and Fill to cover it (which may crop).

Can I enlarge a small image?

You can allow upscaling, but enlarging cannot add detail that is not there. The image will look softer, so downscaling is recommended where possible.

Are my images uploaded to a server?

No. Every image is decoded, processed and encoded entirely inside your browser using the Canvas API. The files never leave your device and are discarded when you close the page.