Convert an image to WebP, JPEG or PNG — in the browser

Write as

The page does not assume what your browser can write. When it loads, it asks the canvas for a tiny WebP and a tiny AVIF and looks at what comes back; the HTML standard says a browser that does not support a format answers with a PNG instead. A format your browser cannot write is switched off, and the line above the buttons names what it can. Many browsers today have no AVIF encoder behind the canvas, so on most of them AVIF stays off, and the page says so rather than hand you a PNG called AVIF.

What you can put in

Anything this browser can decode: JPEG, PNG and WebP everywhere this page runs, and HEIC or AVIF where the browser has the decoder. If it has not, the card says the browser cannot decode HEIC, still shows you the file’s metadata, and converts nothing — it never pretends.

What conversion changes

Metadata. None of it is carried over. The new file is written from pixels, and a canvas has no EXIF, no GPS and no XMP to give; the page reads the new file back to show that. Converting is therefore one more way to get a clean copy — at the cost of re-encoding.

Rotation. The picture is decoded the right way up, following its Orientation tag, so the new file needs no tag. Colour. A canvas works in sRGB unless asked otherwise, and this page does not ask. A picture in a wider colour space is converted to sRGB when it is drawn, and the original’s ICC profile is not carried into the new file; some browsers write a standard sRGB profile of their own, and the card says when one did.

Quality. The slider’s number, 1 to 100, is what the encoder is given on the standard’s 0.0-to-1.0 scale. What an encoder does with a given number is its own business: the same number does not mean the same thing to a JPEG encoder and a WebP encoder. Animation. One canvas makes one still picture, so an animated file comes out as its first frame.

A batch, and the limits

Add many photos and press Convert all: each comes out in the chosen format, on its own card, and Download all packs every result into one ZIP written in the page. A canvas has a maximum size that depends on the browser and the device. Before drawing, the page makes the canvas, puts one pixel in its far corner and reads it back; if the pixel is not there, the canvas is past the limit, and the page tells you so instead of writing an empty picture. Pictures over 100 megapixels are not decoded at all, and files over 300 MB are not read. To change nothing but the metadata, strip it losslessly instead.

How to check that nothing is uploaded. The page’s own scripts make one request of their own — the sample card, from this site, when you press for it — and none that carries a file. The folder is served with a Content-Security-Policy header that lets the page connect only to this site and to Google’s analytics hosts, so even a mistake here could not send a photo anywhere else: the browser would refuse it. Open the developer tools, choose the Network tab, clear it, then add a photo and run the tool, and watch. Google’s analytics counts the visit and that a tool was used; nothing in this page hands it a file name, a pixel or a tag.