Image Resizer
Resize any JPG, PNG or WebP image by width, exact dimensions, percentage or a maximum box, with the aspect ratio kept correct.
Convert with this tool
or choose a file from your device — it is processed in this tab and never uploaded
Accepted: JPEG, PNG, WebP, GIF (first frame), AVIF, BMP, SVG (rasterised)
Files stay on your device. There is no upload, no queue and no watermark, so a conversion works even with the network switched off after the page has loaded.
Supported formats & processing
| Accepted input | JPEG, PNG, WebP, GIF (first frame), AVIF, BMP, SVG (rasterised) |
|---|---|
| Produced output | JPEG, PNG or WebP at the new dimensions |
| Processing | Web Audio API + canvas + native JavaScript encoders |
| Upload required | No — the file is read locally and never transmitted |
How to use this tool
- Drop the image inA preview appears immediately so you can see what you are working with.
- Choose the resize methodBy width for a target column size, exact for a specification, percentage for a quick scale, fit for a maximum box.
- Enter the valueThe other dimension is calculated automatically unless you chose exact.
- Pick the output format and qualityKeep JPEG for photos, PNG for graphics with transparency, WebP for web delivery.
- Convert and compareThe result card reports both sets of dimensions and the size change.
About this tool
Resizing is the most common image operation there is, and it is easy to get wrong. Stretching a photo to a size that does not match its aspect ratio distorts it; resizing an already-small image upward produces a soft, interpolated result that no amount of sharpening fixes.
This tool resizes with the browser's own high-quality canvas resampling and, when you choose a single dimension or a fit box, it calculates the other dimension from your image's real aspect ratio so nothing is ever distorted. The result card reports the source and output dimensions side by side so you can confirm the change before downloading.
Features
- Five resize methods covering every practical case
- Aspect ratio preserved automatically for width, height and fit modes
- High-quality canvas image smoothing rather than nearest-neighbour
- Instant preview of the source before you commit
- Output to JPEG, PNG or WebP with a quality slider
- Transparency preserved in PNG and WebP, flattened for JPEG
Frequently asked questions
Can resizing make my image sharper?
No. Resizing only redistributes the pixels that exist. Making an image larger by interpolation produces a softer result, and making it smaller discards detail. What a downscale does do is make the image look crisper on screen because each displayed pixel maps more closely to a real one.
What happens if I choose an exact size with the wrong ratio?
The image is stretched. Choose By width instead and the height will be calculated to match the original proportions.
What is the best format for the web?
WebP for photographs at roughly 25–35 percent smaller than JPEG at the same quality, PNG for graphics with flat colours or transparency, and JPEG when every browser and application must open the file.
Why does my PNG get larger when I resize it down?
If you change the format to JPEG or the quality slider is very high, the encoder can produce more bytes than the source had. Compare the reported sizes and lower the quality or keep the original format.