Toolsel

Image Resizer

Runs in your browser

Resize an image to exact dimensions or a percentage, with aspect ratio locked.

What is an Image Resizer?

Resizing changes an image's pixel dimensions — a 4000×3000 photo straight off a camera becomes a 1200×900 image sized for a web page, for instance. It's different from compression: resizing reduces the actual number of pixels, which shrinks file size as a side effect but also changes how large the image displays.

Locking the aspect ratio keeps width and height proportional so the image doesn't stretch or squash — entering a new width automatically calculates the matching height. Unlocking it allows an exact width and height independently, useful for fitting a specific slot, but any mismatch from the original proportions will distort the image.

How to use it

  1. Drop an image onto the panel.
  2. Enter a target width or height — with aspect ratio locked, the other dimension calculates automatically.
  3. Or use a percentage preset (25%, 50%, 75%) to scale proportionally without doing the maths.
  4. Choose an output format and quality if applicable, then download the resized image.

Example

Scaling down for web use

Input
photo.jpg — 4000×3000
Output
photo.jpg — 1200×900

Frequently asked questions

Will resizing stretch my image out of proportion?
Not with aspect ratio locked, which is the default — changing the width automatically recalculates a proportional height, so the image scales cleanly. Unlock it only if you deliberately need an exact width and height that don't match the original proportions.
Can I make an image larger than the original?
Yes, technically, but resizing up doesn't add real detail — the extra pixels are interpolated from the ones that already exist, so the result looks softer than a genuinely higher-resolution source. Resizing down loses no meaningful quality; resizing up should be a last resort.
Does resizing also reduce file size?
Usually, yes, since fewer pixels generally means less data — but the main lever for file size is the Image Compressor's quality setting. Use both together for the smallest result: resize to the dimensions you actually need, then compress.
Is my image uploaded to resize it?
No. Resizing is done with the Canvas API entirely in your browser. The file is never sent to a server.