onlinetools.dev

Image Resizer

Resize images by width, height or percentage — sharp and entirely offline

Runs locally
loading…
About this tool

Resize an image to an exact width, an exact height, or a percentage of the original — the other dimension follows automatically so nothing gets stretched. Pick an output format (or keep the source format), set quality for lossy targets, preview the result, and download. Before/after tiles show dimensions and file size at a glance.

Scaling uses the browser's high-quality smoothing mode, which applies proper resampling rather than nearest-neighbor decimation — downscaled photos stay crisp instead of shimmering with aliasing. Resizing is also the honest way to shrink file size: halving both dimensions removes three quarters of the pixels, which no quality slider can match.

Files never leave the page: decoding, resampling and re-encoding all run on a local canvas. There is no upload progress bar because there is no upload — a 40-megapixel photo resizes as fast as your machine can redraw it, and works with the network cable unplugged.

Frequently asked questions

Will resizing down and back up restore my image?
No — downscaling discards pixels permanently. Scaling a 3000px photo to 300px keeps 1% of the data; enlarging it back interpolates the missing 99% as blur. Keep the original file and export resized copies from it, rather than resizing the only copy you have.
Why does my upscaled image look soft?
Enlarging cannot create detail that was never captured — the browser interpolates between existing pixels, which reads as softness beyond about 2×. Genuine upscaling beyond that needs ML-based tools that hallucinate plausible detail; a canvas resampler deliberately does not invent anything.
How do I hit a target file size, like "under 200 KB"?
Work both levers: first resize to the largest dimensions you actually need (a 1200px-wide image is plenty for most web layouts), then choose WebP or JPEG and lower quality until the size tile reads under target. Dimension reduction does most of the work — quality tweaks fine-tune the rest.
Does resizing strip EXIF metadata like GPS location?
Yes. The canvas pipeline re-encodes pure pixels — camera model, timestamps, GPS coordinates and every other EXIF tag are gone from the output. That is usually a privacy win for images headed to the public web; if you need metadata preserved, keep the original alongside.
Related tools