Image Compressor & Converter

How to use

Pick your output format (WebP, JPEG, or PNG), set the quality and maximum dimensions, then click to select one or more images. Each image is compressed and converted in your browser, and you'll see the original vs. new size with the percentage saved. Download each result individually. Nothing is uploaded — your files stay on your device.

Does this upload my images anywhere?

No — and that's the architecture, not a promise in a policy document. Compression happens inside the page you already have open: the browser decodes your file onto a <canvas>, redraws it at whatever dimensions you asked for, and re-encodes it using the browser's own WebP, JPEG and PNG encoders. There is no upload step to opt out of, because there is no server anywhere in the path.

Three things follow from that, all of which you can check yourself:

• No upload wait. A 40 MB photo compresses at the speed of your processor, not your connection — and a batch of twenty costs no round trips at all.
• Confidential files are safe to use here. Passport scans, signed contracts, medical images, screenshots containing customer data — none of it is transmitted, so none of it can be logged, cached or retained by us. There is nothing for us to hand over.
• No upload size cap. Sites that compress on a server have to limit file size to protect their bandwidth bill. The only ceiling here is your device's memory.

It also means the tool works when your connection doesn't. Once this page has loaded you can go fully offline and compression still runs — useful on a plane, on bad hotel wifi, or on a corporate network that blocks file-upload sites outright. If you want to confirm any of this, open your browser's network tab and compress an image: you'll see no request leave.

How image compression works

Digital images can be stored in different formats, each making a different trade-off between file size and quality. Lossy formats like JPEG and WebP discard detail the human eye is least likely to notice, achieving dramatic size reductions. Lossless formats like PNG preserve every pixel exactly, which keeps quality perfect but produces larger files.

This tool does two things: it can convert between formats (e.g., a large PNG screenshot into a compact WebP) and resize images down to a maximum dimension. Combined, these often cut file size by 60–90% with no visible quality loss — which speeds up your website, saves storage, and makes images faster to email or upload.

Modern browsers can do all of this natively through the Canvas API and WebAssembly codecs, so there's no need to send your image to a server. That's faster (no upload wait), private (nothing leaves your device), and free (no server cost).

How do I convert a PNG to WebP?

Set the format dropdown to WebP, leave quality at 80–85%, then select your PNG. That's the whole recipe — the download you get back is a genuine .webp file, not a renamed PNG. Screenshots and UI exports are where this pays off most: PNG has to store every pixel exactly, so a full-page screenshot routinely lands at 3–5 MB, while the same image as WebP is usually under 300 KB.

The conversion runs both directions and between all three formats, so WebP → PNG works too if you need to paste into software that predates WebP support. One exception worth knowing: converting a PNG that has a transparent background to JPEG will fill the transparency with black, because JPEG has no alpha channel. Choose WebP instead — it keeps transparency and is still far smaller than the PNG.

Can I reduce image size without losing quality?

It depends on what you mean by "without losing quality", and the honest answer splits in two:

• Mathematically lossless — every pixel identical to the original. Choose PNG. Nothing is discarded, but the savings are modest and, on photographs, the file often gets bigger.
• Visually lossless — no difference you can see at normal viewing size. This is where the large savings live. WebP or JPEG at 80–85% quality typically cuts a photo by 70–90% while looking identical unless you zoom in and hunt for artifacts.

For almost every real task — email attachments, website images, upload limits — visually lossless is what you actually want, and it is what the default settings give you. The bigger saving is usually dimensional rather than compressive: if an image will be displayed 800px wide, lowering the max dimension to 800px discards data you were never going to see, which is lossless in every sense that matters. Keep the original file either way, because lossy compression is one-way.

Worked example

You have a 4.2 MB PNG screenshot to attach to a support ticket that caps attachments at 2 MB. Choose WebP format, set quality to 80%, and leave max width at 1920px. The tool processes it instantly: 4.2 MB → 380 KB, a 91% reduction, with no visible difference at normal viewing size. Download the WebP and attach it — comfortably under the limit. If the ticket system only accepts JPEG, switch the format to JPEG and reprocess; you'll get a similarly small file in the compatible format.

Tips and common mistakes

• Use WebP for the web. It's smaller than JPEG at the same quality and is supported everywhere modern. Reserve JPEG for systems that don't accept WebP.
• Don't convert photos to PNG to "improve" them. PNG can't add detail that isn't there, and it makes photos much larger. PNG is for graphics with transparency or sharp edges, not photographs.
• Resize before you compress if the image is huge. A 6000px photo displayed at 1200px wastes data. Lowering the max dimension to what you actually need is often the biggest single saving.
• Watch quality below 60%. Aggressive compression introduces visible blocks and blur, especially around text and edges. Preview the result before committing to a very low setting.
• Keep an original backup. Lossy compression is one-way — you can't recover discarded detail. Always keep your source file if you might need the full-quality version later.
• Check which megabyte the limit means. A "2 MB" cap is sometimes 2,000,000 bytes and sometimes 2,097,152 — the MB-versus-MiB gap is about 5%, enough to fail an upload that looks like it should pass. The data size converter settles which one you're up against.