Image Resizer & Compressor — Resize and Convert
Choose an image, set a target width or a percentage, pick a format and quality, and download the smaller file. Nothing is uploaded — the whole conversion runs on your device.
or drag an image here
Choose an image to begin.
What this tool does
It changes two things about an image: how many pixels it has, and how those pixels are stored. Both make a file smaller, and in practice the pixel count matters more — a modern phone photo is far larger than any web page needs, and scaling it down removes most of the weight before any compression setting is touched. The tool also converts between formats, which is how you turn a large PNG screenshot into a small WebP for the web.
Method
The chosen file is decoded by the browser, drawn onto a canvas at the new dimensions, and re-encoded with the format and quality you set; the pixels never leave the page. The target dimensions are worked out from the original aspect ratio so nothing is stretched:
| Mode | Rule |
|---|---|
| Target width | new height = height × (target ÷ width) |
| Target height | new width = width × (target ÷ height) |
| Percentage | both axes scale by the percentage |
| Fit inside a box | the largest scale that keeps both sides within the box |
By design the tool does not enlarge an image: asking for 2000 px from a 900 px original leaves it at 900 rather than inventing pixels. That default is why the note under the result reports the actual output size.
Reducing a file to a target size
Forms often cap an upload at 100 KB or 200 KB. To hit one, lower the quality first and watch the result, then reduce the width if it is still too large. Quality 0.8 is usually indistinguishable from the original at normal viewing, 0.6 is acceptable for a photo that will be seen small, and below about 0.4 the blocking becomes visible. Switching PNG to WebP or JPEG often does more than any quality tweak, because PNG does not compress photographic detail at all.
Example
| Original | Action | Typical result |
|---|---|---|
| 4032 × 3024 phone photo, 4.1 MB | 1920 px wide, WebP q0.8 | ≈ 250 KB |
| 2000 × 1500 photo, 1.8 MB | 50%, JPEG q0.8 | ≈ 320 KB |
| 3000 × 2000 screenshot, 900 KB PNG | Fit in 1200 × 1200, PNG | ≈ 260 KB |
| 800 × 600 photo, 90 KB | 800 px wide, JPEG q0.5 | ≈ 45 KB |
Figures are typical, not promises: the size depends on the picture, so the tool reports the real output for your file rather than an estimate.
Everything runs in your browser; your image is never uploaded. Re-encoding a JPEG or WebP image is lossy, so keep the original if you may need full quality later.
Frequently asked questions
Where should I start to make an image smaller?
Two levers matter: the pixel dimensions and the JPEG quality. Shrinking a 4032 × 3024 phone photo to 1920 px wide throws away more bytes than any quality setting, and it is usually enough on its own. If you need the file under a fixed size — many forms demand “under 100 KB” — drop the quality as well and watch the output size update as you type.
Will quality be lost?
Resizing always resamples the pixels, and JPEG re-encodes them, so there is some loss. The tool tries to keep it invisible: you choose the output size rather than guessing, the preview shows the result at its real size, and PNG output is available when you need a lossless copy or transparency.
Which format should I choose?
WebP is smallest for photographs and supported by every current browser. JPEG is the safest for anything that leaves the web — email, print, older software. PNG is lossless and keeps transparency but is much larger for photos; it is the right choice for screenshots, logos and diagrams with flat colour.
Is my image uploaded to a server?
No. The file is read and redrawn on a canvas inside the page, and the download is produced from that canvas. Nothing is sent anywhere, and the tool keeps working if you go offline after the page has loaded.
Why does the size I asked for come out a little different?
The output width and height are rounded to whole pixels while the aspect ratio is preserved, so one axis may differ by a single pixel on an odd ratio. The result panel shows the exact dimensions before you download.
Can I resize several images at once?
This tool does one image at a time so you can check the result before saving. Resize the largest offenders first — compression savings are concentrated in the biggest files.
Go deeper
Longer explanations of the problems this tool solves:
Sources
- HTML Living Standard, the
<canvas>element and its 2D drawing context, used to resample and re-encode the image in the browser. - Google, WebP image format documentation — compression and browser support. developers.google.com/speed/webp
Everything runs in your browser — nothing you type is uploaded.