Image Resizer
Resize and compress an image to JPEG, WebP, or PNG — entirely in your browser.
Everything runs in this tab — the file is never sent anywhere.
Enlarging an image cannot add detail — scaling a 400px photo up to 1200px produces a soft result, not a sharper one. Resizing down is where the real saving is.
Most oversized images are simply too large in pixel dimensions. A 4000-pixel-wide photo displayed in a 800-pixel column wastes about 96% of its data. Resizing to the size actually shown, then compressing, is what makes the difference.
Dimensions first, quality second
When a file is too big, the instinct is to crank compression down. That is the wrong lever to pull first. A photo displayed 800 pixels wide gains nothing from being 4000 pixels wide, and since file size scales with the area, halving both dimensions cuts the pixel count to a quarter before any compression is applied.
Only once the dimensions are right does quality matter. For photographs, JPEG or WebP at around 75–85% is usually indistinguishable from the original at normal viewing size, while producing a fraction of the bytes.
Choosing a format
JPEG suits photographs and anything with smooth gradients. It is lossy and has no transparency, but it is universally supported. WebP does the same job roughly 25–35% smaller and does support transparency; every current browser handles it, though very old software may not. PNG is lossless, which makes it right for screenshots, diagrams, and logos with flat colour or sharp edges — and wrong for photographs, where it produces enormous files.
The distinction that matters is the content, not the quality setting: a screenshot of text saved as JPEG develops visible fringing around the letters at any quality, while the same image as PNG stays crisp and often smaller.
How to use it
Load, resize, then compress:
- 1 Choose a file. It is read into the page directly and never uploaded, so even a large photo loads instantly.
- 2 Set the width you actually need. For a web page, match the column it will sit in — 1200px is generous for most layouts.
- 3 Leave the aspect ratio locked. The height follows automatically. Unlocking it lets you distort the image, which is rarely what you want.
- 4 Pick a format. JPEG or WebP for photographs, PNG for screenshots and graphics with flat colour.
- 5 Adjust quality if needed. Start at 80. Drop it until the result looks wrong, then go back one step.
- 6 Compare and download. The result shows the new size and the percentage saved against the original.
Choosing dimensions and format
Sensible starting points. The right width is whatever the image is actually displayed at, doubled if it must stay sharp on high-density screens.
| Use | Typical width | Format |
|---|---|---|
| Email attachment | 1200 px | JPEG at 75 |
| Web page body image | 1200 px | WebP or JPEG at 80 |
| Full-width hero image | 2000 px | WebP at 75 |
| Thumbnail | 400 px | WebP or JPEG at 80 |
| Screenshot of text or UI | Original | PNG |
| Logo or diagram | Original | PNG |
| Profile photo | 600 px | JPEG at 85 |
What resizing cannot do
Enlarging does not add detail. Scaling a 400-pixel image up to 1200 gives you a 1200-pixel image containing 400 pixels of actual information, spread thinner — the result is soft, and no quality setting fixes it. The saving is always in going down.
Re-encoding also compounds. Every time a JPEG is decoded and saved again it loses a little more, even at high quality, because the compression is not reversible. If you will need several versions, make each one from the original rather than from the last export.
Occasionally the output comes out larger than the input. That normally means the original was already well compressed and you have re-encoded it at a higher quality than it was saved with, or converted a photograph to PNG. The fix is a lossy format and a lower quality, not more compression of the same kind.
Everything here runs through the browser's canvas, so the file is read locally and never sent anywhere. That also means the practical size limit is your device's memory rather than any upload cap.