MultiKit

Resize Image: Change the Size of JPG, PNG and WebP Pictures

  • Free
  • No sign-up
  • Runs in your browser
  • Version 1.0.3
  • Last updated 2026-10-30
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Make pictures smaller or larger by setting a width in pixels, a height, both, or a percentage. Every picture keeps its own format.

    Everything you enter is processed in your browser and is never sent to a server.

    Browsers:Chrome57+Edge79+Firefox52+Safari15+Opera44+Samsung Internet7.0+Browsers

    How to use

    1. Drop your pictures onto the box, or choose them. Up to 50 at once.
    2. Choose how to set the size: by width (the height follows), by height, by both, or by percent. The width is set to 1200 pixels to start with.
    3. Check the new size and file size in the list, then download each picture or all of them as a ZIP.

    Examples

    A 4000×3000 JPG, width 1200
    → 1200×900
    Setting only the width keeps the shape of the picture.
    A 1920×1080 PNG, 50%
    → 960×540
    photo.PNG, resized
    → photo.png
    The format and the name stay the same.

    How it works

    This page is the image converter set to keep each file’s format and to resize by width. The new size is worked out in whole pixels: setting a width of 1200 for a 4000×3000 picture gives a height of 3000 × 1200 / 4000 = 900. The picture is resampled with the Lanczos filter from the jSquash library, then saved by MozJPEG, libwebp or a PNG encoder, all compiled to WebAssembly.

    The size calculations, the file naming and the format choice are tested.

    Sources

    Frequently asked questions

    How do I resize a picture without stretching it?
    Set only the width, or only the height. The other side is worked out from the shape of the picture. Setting both at once, with a different shape, stretches it.
    Which size should I choose?
    For a web page, 1200 to 2000 pixels wide is usually plenty. For e-mail, 1024 pixels wide is common. For a social media picture, check the size the site asks for. For print, keep as many pixels as possible.
    Does making a picture larger make it sharper?
    No. Pixels are added by calculation and cannot bring back detail that was never there, so enlarged pictures look soft. It works best for making pictures smaller.
    Will the file get smaller?
    Usually, a lot, since fewer pixels mean less data. The list shows the real change for each picture. You can also lower the quality of JPG and WebP pictures at the same time.
    Which resizing method is used?
    A Lanczos filter, which keeps more detail than the quick scaling a browser does by itself.
    Are my pictures uploaded?
    No. They are resized in your browser.
    Version history
    • 1.0.3 — Puts the format and quality options and the size options on one line on a wide screen, instead of two lines with empty space beside them.
    • 1.0.2 — Makes the search title and description state the supported task, key formats and privacy benefit more clearly.
    • 1.0.1 — Reports conversion completion and failure to connected workflows, so batch runs wait for the full result and ignore cancelled or superseded work.
    • 1.0.0 — First release.

    Last updated: