Image Resizer
Resize an image to exact pixel dimensions in the browser, with step-down scaling that keeps detail instead of smearing it.
Resize images online to exact pixel dimensions — step-down scaling keeps detail instead of smearing it, and nothing is uploaded because it all runs in your browser.
Steps and notes
What is Image Resizer?
Resize an image to the exact width and height you need, entirely in your browser — the file never leaves your machine. The important part is how the shrinking is done: a canvas will happily scale 4000×3000 straight down to 400×300 in one step, and the browser's bilinear sampling simply discards most of the pixels, which shows up as jagged edges and moire on patterns and text. This tool instead halves the image repeatedly until it is within two steps of the target, then does the final adjustment, which is the closest thing to a proper resampling filter you can get without a native library. Output is PNG (lossless), or JPEG/WebP where you control the quality. Formats are offered only if the browser actually encodes them: the spec says an unsupported type should make toBlob return null, but Chrome, Safari and Firefox quietly return a PNG instead, so the option list is probed at runtime rather than assumed.
- Pick an image
- Enter the target width and height (or keep the aspect ratio locked)
- Choose the output format and download the result
- Downscaling is done by repeated halving rather than one big jump — a single canvas scale throws away pixels and leaves aliasing.
- Enlarging beyond the original resolution cannot add detail; the result will be softer, not sharper.
- Only formats the browser can genuinely encode are offered — see the question about formats below.
Frequently asked questions
- Why is my resized photo sharper than one from another resizer?
- Because shrinking happens in repeated halving steps instead of one jump. A single large downscale makes the browser sample too sparsely and drop detail; halving keeps each step close to 2:1 so information is averaged rather than skipped.
- Can I make a small image bigger without losing quality?
- No tool can invent detail that was never captured. Enlarging here resamples the existing pixels, so the result is larger but no sharper — expect it to look softer. The exception is pixel art, where nearest-neighbour style scaling keeps hard edges.
- Which output formats are available?
- PNG always, plus JPEG and WebP when your browser genuinely encodes them. Formats the browser cannot really produce are not listed at all, rather than being listed and silently producing a different file type.
- Why should I resize locally instead of using an online converter?
- Because an ID card, a contract scan or a private photo does not need a second home on someone's server. Nothing is uploaded here, so there is no retention policy to trust and no breach to worry about.
- What are the size limits?
- The practical ceiling is your device memory, not a server quota. Very large images (roughly beyond 8000 pixels on a side as capped in the fields) can fail in the browser, and the tool reports the failure instead of returning a truncated file.
Category: Images and videos
Image tools workflow
Image Resizer → Image Compressor → Image Cropper → Images to PDF → Favicon Generator → SVG placeholder generator → Camera Recorder