What This Tool Does
This resizer changes an image's dimensions — shrink it down for a faster-loading web page, enlarge it for a print, or fit it neatly into a fixed box for a template. Drop one file or fifty; each one is resized (and optionally rotated) using the setting you choose, and you download the result with a single click.
Everything happens on your device. There's no upload step, no processing queue on a remote server, and no size limit imposed by a backend — the only ceiling is what your browser's memory can hold.
Three Resize Modes
| Mode | What you enter | Aspect ratio | Best for |
|---|---|---|---|
| Pixels | Exact width and/or height in pixels | Kept if you leave one field blank; distorted if you fill both | A precise target size, e.g. 1200×630 for a social banner |
| Percent | A single scale value, 1–400% | Always kept | Quick shrinking or enlarging relative to the original, e.g. "50% smaller" |
| Fit in box | A bounding width and height in pixels | Always kept | Making a batch of differently-shaped photos all fit inside the same maximum size |
Switch modes with the segmented control above the drop zone — your files are processed with whatever mode and values are active at the moment you drop them.
Pixels Mode and Aspect Ratio
In pixels mode, leaving either the width or the height field blank tells the tool to calculate that dimension automatically so the image keeps its original proportions. For example, a 1600×900 photo resized to a width of 800 with height left blank becomes exactly 800×450 — the same 16:9 shape, just smaller.
Fit-in-Box Mode
Fit-in-box is the safest option when you're processing a batch of images with different original shapes (say, a mix of portrait and landscape photos) and want them all to fit within the same maximum size, like 800×800 for a product gallery. The tool scales each image down until it fits entirely inside the box you specify, keeping its aspect ratio — a wide photo ends up limited by the box's width, a tall photo by its height.
Rotating Your Images
The Rotate dropdown supports 0° (no change), 90°, 180°, and 270°, applied clockwise. Rotation happens together with whatever resize mode is active, so you can straighten out a sideways phone photo and resize it in a single pass — or just rotate without resizing at all by leaving the pixel fields blank.
Resize Quality: Lanczos3 Filtering
Every resize in this tool uses the Lanczos3 resampling filter, a high-quality algorithm that produces sharper results than simpler methods like nearest-neighbor or basic bilinear scaling, especially when shrinking an image. It's the same class of filter used by professional image-editing software for general-purpose resizing.
Your Files Never Leave Your Device
The resize runs through a small WebAssembly module loaded into your browser tab. When you drop a file, its bytes are read locally and handed to that module — they're never sent anywhere over the network. Closing the tab discards everything; there's nothing left behind on a server because there was never a server involved in the first place.
If you also need to convert an image to a different file format, see the Image Format Converter. For resizing to specific platform requirements (app icons, social banners, favicons), see the Logo & Image Resizer tools — both use the same on-device approach.