Resize image
The Image Resizer shrinks or enlarges a photo to a target width in pixels. With "keep aspect ratio" enabled the height is calculated automatically, so the image never gets distorted. It is ideal for resizing photos for the web, e-mail or an avatar. Everything runs directly in your browser — the image is never uploaded and never leaves your device.
How image resizing works
The tool loads your image onto a hidden HTML canvas in the browser and redraws it at the new dimensions. You enter the target width in pixels; the height is handled in one of two ways depending on the "keep aspect ratio" checkbox:
- Ratio kept (default): the height is derived proportionally with
new height = round(new width × original height ÷ original width), so the shape of the image stays faithful. - Ratio off: the height stays at the original value and only the width changes — the image is stretched or squeezed horizontally.
The rescaling is done by the browser's rendering engine, which interpolates (smooths) between pixels — that is why downscaling looks clean and free of jagged edges. The result is always exported as PNG, a lossless format, regardless of the format you uploaded. Both the resizing and the export run locally; no data is sent to any server.
How to use the image resizer
- Drag an image onto the drop zone or click to pick a file (JPG, PNG, WebP and more).
- Enter the desired width in the New width (px) field. After upload it is pre-filled with the original width, capped at 1600 px.
- Leave keep aspect ratio ticked unless you deliberately want to distort the image.
- Click Resize. A preview and the new dimensions appear.
- Download the result with the Download button — the file is named like
name-800px.png.
Example: a 3000 × 2000 px image with a target width of 800 px and the ratio kept:
| Input | Settings | Output |
|---|---|---|
| 3000 × 2000 px | width 800, ratio on | 800 × 533 px (PNG) |
| 3000 × 2000 px | width 800, ratio off | 800 × 2000 px (PNG) |
What image resizing is good for
Reducing the width is the fastest way to lighten large photos from a phone or camera before uploading them to a website, e-mail or document — smaller dimensions mean a much smaller file and faster loading. Typical scenarios:
- Preparing thumbnails and illustrations for a blog or e-shop at a specific content width.
- Scaling a profile photo or avatar down to a required size.
- Unifying the width of a set of images so they look consistent on a page.
- Quickly shrinking a photo that has to fit an e-mail attachment limit.
Because the tool runs entirely in your browser, it also suits sensitive or private images — documents, screenshots, family photos. Nothing is uploaded to a third-party server, so the data stays with you. Tip: if you care less about dimensions and more about the smallest possible file at the same size, reach for the Image Compression tool, which lowers JPG/WebP quality instead of the pixel count.
FAQ
Does resizing reduce the image quality?
When downscaling the loss is minimal — the browser interpolates pixels smoothly, so the smaller image stays sharp. When enlarging beyond the original size, however, no new detail is created; the image is just stretched and may look blurry or jagged.
What format is the image saved in?
The output is always PNG, no matter which format you upload. PNG is lossless, so resizing adds no extra compression loss. If you need JPG or WebP, use the Image Format Converter tool.
Can I also enlarge an image?
Yes, you can enter a width of up to 10000 px. Enlarging does not add detail that isn't in the original, though — the tool only stretches the existing pixels, so the result will be less sharp than the original smaller image.
Is my image uploaded to a server?
No. All processing runs directly in your browser via the HTML canvas. The image never leaves your device, and no sign-up or connection to any service is required.
How is the height calculated when I only enter a width?
With "keep aspect ratio" enabled the height is computed as new width × original height ÷ original width and rounded to whole pixels. The aspect ratio therefore stays identical to the original.
What happens if I turn off keeping the aspect ratio?
Only the width changes while the height stays at its original value. This stretches or squeezes the image horizontally — useful only in rare cases, otherwise it causes distortion.
Does the tool support transparency (PNG with an alpha channel)?
Yes. The output is PNG, which supports transparency, so a transparent background from an input PNG or WebP is preserved after resizing.
Why is the width set to 1600 px after upload even though my photo is larger?
The tool pre-fills the field with the original width but caps it at 1600 px to offer a sensible default for the web. Feel free to overwrite it with any width from 16 to 10000 px.
Sources & standards
📅 Last updated: 11 July 2026