Image Compressor
Compress an image to a quality you choose, or to a file size limit you actually have to meet.
Pixels. 0 keeps the original. Downscaling saves more than any quality setting.
Drop an image here
or paste a screenshot with Ctrl+V. Nothing is uploaded.
Everything here runs on your device. Nothing you enter is uploaded or stored.
Most compressors give you a quality slider and leave you guessing. That is fine until something tells you the file must be under 500KB, at which point a quality percentage is the wrong unit entirely and you end up exporting the same image six times to find one that fits.
How to use it
- Drop an image onto the panel, press Choose images, or paste from your clipboard.
- Compress by quality for a generally smaller file, or to a file size when you have a hard limit to meet.
- Optionally cap the width. This is usually the biggest saving available and the one people forget.
- Check the before-and-after figures, then press Download. Select several files first for a ZIP.
Why targeting a file size is the whole point
Nobody wants “quality 70”. People want “under 2MB, because the visa application portal rejects anything larger”.
The two are not interchangeable, and the reason is worth understanding. Lossy encoders work by discarding detail your eye is unlikely to miss. How many bytes that saves depends on how much detail there was to begin with. A busy photograph gives the encoder very little to throw away, so it stays large even at low quality. A simple graphic with flat colour compresses to almost nothing. The same quality setting can therefore produce a 40KB file from one image and a 1.2MB file from another.
The only way to hit a byte target is to encode, measure, and adjust. That is a binary search: try the middle quality, see whether the result is over or under, then halve the remaining range and try again. Six or seven attempts lands within a few kilobytes of any reachable target, and it happens fast enough to feel instant because it all runs locally.
When a target genuinely cannot be reached — a very large image with a very small limit — the tool says so plainly and tells you to reduce the width, rather than handing you a file that misses the limit and calling it done.
The saving everyone forgets
A photo straight off a modern phone is around 4000 pixels wide. Displayed in a web page it might occupy 800. The other 3200 pixels of width are being downloaded, decoded and then thrown away by the browser.
Cutting the width to what you actually need removes about 96 per cent of the pixels in that example, and file size follows pixel count far more directly than it follows quality. Halving the dimensions typically beats dropping quality from 90 to 50, and it costs nothing visible because the extra resolution was never being seen. If your image is going into a web page, an email or a document, cap the width first and then worry about quality.
Format advice, given honestly
When you load a file, the tool samples it and says something useful about the format. A PNG containing a photograph is the single most expensive mistake in this area and it is extremely common — the file is often several times larger than it needs to be, and converting to JPEG or WebP fixes it in one step.
If the image has genuine transparency, WebP is recommended instead, because it keeps the alpha channel while compressing far better than PNG. If you are already working with a JPEG, WebP will typically save another 25 to 35 per cent at the same visual quality.
What it does not do
It cannot recover quality that has already been lost, so compressing a file that was compressed before will always look worse than working from the original. It does not do true lossless PNG optimisation with custom filters, only a browser re-encode. It cannot read RAW, HEIC or SVG, because browsers cannot decode those onto a canvas.
Nothing is uploaded. There is no queue, no daily limit, and no file ever leaves your device.
Real upload limits worth knowing
| Limit | Where you hit it |
|---|---|
| 50 KB | Forum avatars and small profile photos |
| 200 KB | A web page image that should not slow it down |
| 500 KB | Government and job application forms |
| 1 MB | Most CMS and forum attachment limits |
| 2 MB | Visa and passport photo upload portals |
| 5 MB | Email attachments without a warning |
| 10 MB | Gmail and Outlook inline attachment ceiling |
Questions
How do I compress an image to exactly 200KB?
Switch to the file size mode and pick 200 KB, or type your own limit. The tool then encodes the image repeatedly at different quality settings, measuring the actual bytes each time, and keeps the highest quality that still fits under your limit. It usually takes six or seven attempts. No single quality percentage can hit a byte target reliably, because the relationship between quality and file size depends entirely on what is in the picture.
Why does the same quality setting give wildly different file sizes?
Because JPEG and WebP compress detail, not pixels. A photograph of a forest canopy has detail in every square millimetre, so there is very little for the encoder to discard, and quality 40 might still be 900KB. A flat studio background at quality 40 might be 8KB. This is exactly why targeting a file size is more useful than targeting a quality number.
Should I compress a PNG or convert it first?
If the PNG holds a photograph, convert it to JPEG or WebP — that will often make it five to ten times smaller, far more than any PNG optimisation can. PNG is lossless, so the only savings available are in how the pixels are stored, not in discarding detail. The tool detects a photographic PNG and says so when you load one.
Does compressing an image more than once make it worse?
Yes, for lossy formats. Every JPEG or WebP save discards detail permanently, and compressing an already-compressed file discards more on top of what has already gone. The artefacts compound, and it shows first around text and hard edges. Always compress from the original file rather than from a previously compressed copy.
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