Compress image
Shrink JPG, PNG and WebP file size while keeping quality — locally, no upload.
What image compression actually does
Every JPG, PNG or WebP file stores your picture using a certain amount of data. Compression re-encodes that picture to use fewer bytes — a smaller file that loads faster on a web page, slips under an email attachment limit and takes up less room on your phone or drive. For a typical photo the saving is dramatic: a multi-megabyte JPG straight off a camera often drops to a few hundred kilobytes with no difference you can see.
There are two kinds of saving. Lossy compression (JPG and WebP) throws away detail your eye barely notices to reach a much smaller file, trading a little quality for a lot of size. Lossless compression (PNG) keeps every pixel exactly and simply stores it more efficiently, so the file shrinks less but stays pixel-perfect. imagenimble lets you pick the balance with a quality slider and shows the estimated output size before you download.
Compressing locally in your browser
The whole process runs on your own device. Your image is decoded, re-encoded at the setting you choose and handed straight back to you — nothing is uploaded, so a private photo never sits on someone else’s server. You can confirm it by going offline after the page loads: compression still works, because the file never had to travel anywhere.
Working locally also removes the usual limits. There is no upload cap, no queue and no daily quota; you can drop a whole folder of images and download the compressed set as a single ZIP. The only real ceiling is your device’s memory, which matters only for very large batches of very large files.
Choosing quality and format for the smallest file
For photographs, JPG or WebP at around 75 to 85 per cent quality is the sweet spot — the file shrinks enormously while the result looks identical to the original. WebP usually beats JPG at the same quality and can also keep transparency, so it is the best choice when the target is a modern website. Only drop below about 70 per cent if you specifically need a tiny file and can accept some softening in skies and gradients.
For logos, screenshots, icons and flat graphics with sharp edges, stay with PNG: lossy compression would blur the crisp lines, while PNG keeps them clean and still saves space. If you are unsure, compress once to WebP and once to JPG and compare the size and the look — it takes a couple of seconds.
Compress, resize or convert — which one you need
These three tools solve different problems and are often combined. Compressing keeps the same pixel dimensions but stores them with fewer bytes — reach for it when the picture is the right size but the file is simply too heavy. Resizing changes the pixel dimensions themselves, the biggest single lever on file size: a photo scaled from 4000 to 1200 pixels wide is a fraction of the weight before you compress at all. Converting changes the format, for example PNG to JPG, which can shrink a file dramatically on its own.
A practical order for the smallest possible file: resize to the dimensions you actually need, convert to JPG or WebP, then compress to fine-tune. For a website image that alone can turn several megabytes into well under a hundred kilobytes.
Privacy by design
All processing happens inside your browser. Your files never reach a server — there is nothing to store, transmit or share.
Learn more in our privacy policyBatch & bulk: process multiple images at once
Load not just one image but as many as you like — by drag & drop or multiple-select. imagenimble processes them one after another, locally in your browser, and packages the results as a single ZIP download. No upload, no account and no fixed limit — only your device’s memory caps very large batches. It is the quick way to convert or edit a whole folder in one go.
Frequently asked questions
It depends on the original and your quality setting, but photos often shrink by 50–80% at a quality that still looks identical.
Lossy compression discards some detail, but at moderate settings the change is invisible. The live size estimate helps you find the sweet spot.
Use JPG or WebP for photographs, and PNG for graphics with text, sharp edges or transparency.
No — compression runs entirely in your browser, so files never leave your device.
For most photos you can cut the file to a fifth of the original or less before any loss becomes visible. Keep the quality around 75 to 85 per cent, watch the size estimate, and only push lower if you truly need a tiny file.
Yes. Drop or select as many files as you like and imagenimble compresses them one after another in your browser, then gives you the whole set as a single ZIP. There is no fixed limit beyond your device’s memory.