Convert images between JPEG, PNG, WebP, and AVIF, any to any, entirely in your browser. Your images never leave your device: no upload, no account, no tracking.

What this tool does

A form accepts JPEG and nothing else. A design app exports WebP that a colleague's older software refuses to open. Something arrives as an AVIF and the viewer shows a grey rectangle where the picture should be.

This tool re-encodes an image into a different format, on your machine.

It reads JPEG, PNG, WebP, AVIF, GIF, and BMP, and it writes JPEG, PNG, WebP, or AVIF. You choose one output format for the whole batch and, for the lossy formats, a quality value. Each card shows the source format, the target format, and the new file size, and you can download files one at a time or together as a ZIP.

One cost is worth knowing before you choose, because it is not spread evenly. Each output format pulls its own WebAssembly module the first time you convert to it: roughly 246 KB for JPEG, 338 KB for WebP, 160 KB for the PNG optimizer, and 3.3 MB for AVIF.

So the first conversion to any given format is slower than every one after it, and on a phone data plan AVIF is a decision rather than a free upgrade.

What a format change costs

Three more things catch people out, and none of them is obvious from the file names.

JPEG has no transparency. There is no alpha channel in the format at all. Convert a logo with a see-through background to JPEG and those areas come back filled in solid. If the transparency matters, target PNG, WebP, or AVIF instead; all three carry alpha.

Going the other direction does not repair anything. A JPEG has already thrown detail away, and turning it into a PNG will not bring that detail back. What you get is a lossless copy of a lossy image: a much larger file, and a perfectly faithful recording of every compression artifact the JPEG already had.

Which is the wider point. Converting is not compressing. A conversion can produce a bigger file than you started with, so this tool reports the new size plainly and never claims it saved you anything. If a smaller file is the actual goal, Compress Images is the one built for it.

Animation is the third thing to watch. GIFs and animated WebP files decode to their first frame only, so an animated GIF goes in moving and comes out as one still image. The card says so when the source is a GIF.

Picking a target format

JPEG is the universal one. Every device and every piece of ancient software opens it. No transparency, and fine for photographs.

PNG is lossless and holds sharp edges and transparency, which suits screenshots, logos, and line art. Photographs stored as PNG get large.

WebP is the sensible default for the web now. Smaller than JPEG at comparable visible quality, supports transparency, and opens in every current browser.

AVIF makes the smallest files of the four and costs the most to produce, in both download and encoding time. Worth it for something you are publishing, less so for a quick one-off. If its encoder cannot load, the tool disables AVIF and points you at WebP rather than silently producing nothing.

Where the encoding happens

In a background thread in your browser, using WebAssembly encoders served from this site.

Only the encoder for the format you actually chose gets fetched: mozjpeg for JPEG, oxipng to losslessly shrink PNG output, and the WebP and AVIF encoders for those two, at the sizes listed above. JSZip, roughly 97 KB, is fetched only if you click "Download all (ZIP)". Nothing else is loaded, and no third-party CDN is involved.

Your images are not part of any of that traffic. They are decoded, re-encoded, and handed back as downloads without being sent anywhere. Open the Network tab in DevTools while a batch converts and you can watch the codec arrive and nothing leave.

Decoding also discards the file's EXIF and GPS metadata, so a converted copy says less about where you were than the original did.

There is no account, no tracking, and no upload step to opt out of. The full source is public on GitHub under the AGPL-3.0 license, and the privacy page gives this tool a row for each encoder and the choice that calls for it.

Questions

Is there a free image converter online?

Yes. This page is one.

It is a free online image converter covering JPEG, PNG, WebP, and AVIF, with no upload, no install, no account, and no watermark. The encoders run on your device, and the page fetches only its own code plus the one codec your chosen format needs.

Are my images uploaded anywhere?

No.

Every file is decoded and re-encoded in your browser. No server sees your pictures, because no server is doing the work.

You can verify it instead of believing it: open DevTools on the Network tab and convert something. The encoder for your target format downloads once, and no image data goes the other way.

What happens to transparency if I convert to JPEG?

It is lost. JPEG has no alpha channel, so there is nowhere for it to go.

Transparent areas come back opaque rather than see-through, which is obvious the moment you put the result on a colored background.

If the transparency has to survive, convert to PNG, WebP, or AVIF. All three support it.

Can I convert a JPG to PNG?

Yes, and it is worth knowing what you get.

PNG is lossless, but that does not restore quality the JPEG already lost. It preserves exactly what is there now, artifacts included, and a photographic JPEG usually grows a good deal in the process. The card shows the new size so you can judge the trade.

How do I convert an image to AVIF?

Choose AVIF as the output format and give it a moment. The first conversion pulls down the 3.3 MB encoder, and AVIF is the slowest of the four to run.

In return it makes the smallest files and it supports transparency. If the encoder fails to load, the tool disables AVIF and offers WebP instead of leaving you with nothing.

Can I convert HEIC photos from my iPhone?

Not here. HEIC is a different container that this converter does not read.

HEIC to JPG is built for exactly that and runs the same way, on your device.

Related tools

Compress Images | reduce file size while keeping the format. Resize Image | change pixel dimensions to an exact size or a percentage. HEIC to JPG | convert iPhone HEIC photos to JPG. Photo Editor | crop, redact, and batch-edit images.