Image Compressor

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Input

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Settings

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Run

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Results

Results will appear here once you run the tool.

About Image Compressor

Image Compressor shrinks pictures two ways: pull a quality slider and watch the size fall, or name a target size in kilobytes and let the tool search for the quality setting that lands under it. The second is the one you want when an upload form has told you the limit is 200KB.

Format matters more than the slider. Converting a photograph from PNG to JPEG usually saves more than any amount of quality reduction, because PNG is lossless and stores photographic noise faithfully. WebP typically beats JPEG by 25-30% at the same visual quality, and AVIF beats WebP again — both are supported by every current browser. Keep PNG only for screenshots, logos and anything with sharp edges or transparency.

Resizing is the bigger lever. A 4000-pixel-wide photo displayed in a 800-pixel column is carrying twenty-five times more data than it can show. The width limit here caps the dimensions before compressing, which usually does more for file size than the quality slider ever will.

Transparency needs a decision. JPEG has no alpha channel, so converting a transparent PNG to JPEG has to fill the transparent areas with something — set that colour rather than being surprised by black.

Batch up to a hundred at once, all processed on your own device. No upload means no waiting on a queue and no file size ceiling, and the holiday photos or ID scans you are compressing are not copied to anyone's server.

How to use Image Compressor

Add your images. Drop in up to 100 pictures. They are read and compressed in your browser.
Compress by quality or by target size. Use the quality slider to trade sharpness for size, or switch to target size and name a limit in KB — useful when a form has told you the maximum.
Pick the output format. JPEG for photos going to other people, WebP or AVIF for the web and much smaller files, PNG only for screenshots, logos and transparency.
Cap the width too. Setting a maximum width usually saves more than the quality slider, because most images are far larger than the space they are displayed in.

Frequently asked questions

What quality setting should I use?

Around 75 is a good default for photographs — most people cannot see the difference from the original at normal viewing size. Below about 50 you start to see blocky artefacts in smooth areas like skies.

My PNG barely shrank. Why?

PNG is lossless, so quality has no effect on it. For photographs, converting to JPEG or WebP will save far more. PNG is the right choice for screenshots, logos and anything needing transparency.

Can I hit an exact file size?

Yes. Choose "Target file size" and enter a number in KB. The tool searches quality settings automatically to land just under it.

Are my files uploaded when I use Image Compressor?

No. Image Compressor runs entirely inside your browser. Your file is read locally, processed on your own device, and handed straight back to you. You can confirm this yourself: open your browser's developer tools, watch the Network tab, and run the tool — no request carries your data anywhere.

Is Image Compressor free?

Yes, completely. No account, no sign-up, no watermark on your output, and no cap on how many times you can use it. The project is open source under the AGPL licence.

Is there a file size limit?

There is no server limit, because nothing is uploaded. The practical ceiling is your device's memory — on a modern laptop, files up to a few hundred megabytes are comfortable, while phones handle less. If a tab becomes unresponsive, the file was too large for the memory available.

Can I process several files at once with Image Compressor?

Yes — up to 100 at a time. When there are more than a few results they are packaged into a ZIP so you get everything in one download.

Does Image Compressor work offline?

Mostly. The site caches itself after your first visit, so it keeps working without a connection. Tools that need a specialised library — PDF editing, OCR, QR codes, MP3 encoding — need a connection the first time you run them, then that library is cached too.