Images
How to Compress an Image With No Quality Loss at All
True lossless compression shrinks PNGs by 20-50% without altering one pixel. Here is when it works, when it does not, and what visually lossless means.
7 min read
Image Compressor — Shrink JPG, PNG and WebP
Compress and resize images without uploading them. Convert to WebP, JPG or PNG, adjust quality, and see the exact saving per file.
- Runs entirely in your browser
- No uploads, no servers
- Free, no signup
Drop images here, or
PNG, JPG, WebP, AVIF, GIF or BMP · Processed on your device · Nothing is uploaded
Lower means a smaller file. 70–85% is usually indistinguishable.
Resizing is usually the biggest saving for photos.
WebP is typically 25–35% smaller than JPG at the same quality.
About this tool
Drop in up to 20 images and compress them on your own device — no upload, no queue, no watermark. Choose an output format, set a quality level, and optionally cap the longest edge, which is usually where the biggest saving comes from. Each result shows its before-and-after size so you can judge the trade-off yourself.
The single most effective thing you can do to an image destined for a website is resize it before compressing. A photo straight from a phone is typically 3000 to 4000 pixels wide; a blog column displays it at 800. Capping the longest edge often cuts the file by 80% before quality compression is applied at all.
If you are deciding between formats or trying to understand what the quality slider actually does, the image compression guide covers the reasoning in more detail.
What it does
- Compress JPG, PNG, WebP, AVIF, GIF and BMP
- Convert between WebP, JPG and PNG
- Resize to a maximum width or height
- Batch up to 20 images at once
- Per-file size saving shown
- Nothing uploaded — runs entirely on your device
Frequently asked questions
Are my images uploaded anywhere?
No. Compression uses the browser's own canvas and image encoder. You can disconnect from the internet after the page loads and the tool still works — which is the clearest proof that nothing is being sent.
What quality setting should I use?
75-85% is the practical sweet spot for photographs. Above 90% the file grows quickly with no visible benefit. Below about 70% you start seeing blocking in smooth gradients like skies.
Why did my PNG get bigger instead of smaller?
PNG is lossless, so re-encoding an already-optimised PNG can add a little overhead. For photographs, convert to WebP or JPG instead — PNG is the wrong format for photographic content and will always be several times larger.
Should I choose WebP or JPG?
WebP for anything going on a website — it is typically 25-35% smaller at equivalent quality and every current browser supports it. JPG for files you email or send to someone using older software.
Does resizing lose quality?
Scaling down discards detail permanently, but if the image is only ever viewed at the smaller size you lose nothing visible. A 4000px photo displayed in a 800px column is carrying five times the pixels it needs.
Is there a file size limit?
Individual files up to about 30MB work reliably. Beyond that, browser canvas limits make the result unpredictable, so larger files are skipped rather than silently corrupted.
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