Image converter

A converter that decodes and re-encodes images using the browser’s own codecs, so the file is never transmitted. The consequence that matters is economic rather than technical: there is no per-file cost to the operator, so there is no reason for a file-count cap.

• No batch limit, because there is nothing to meter

  Images are processed one after another rather than in parallel, which is what keeps a phone from exhausting its memory and losing the tab. The practical ceiling is your own device.

  Squoosh has no batch mode at all; Caesium caps a session at ten files; TinyPNG’s web tool stops at twenty.

• Three output formats, with the reasoning

  WebP for almost everything — smaller than both JPEG and PNG at equivalent quality, universally supported since 2020. JPEG when something downstream refuses WebP, accepting that it has no transparency. PNG only for flat graphics, screenshots and hard edges, because it is lossless and therefore the wrong choice for a photograph.

• EXIF and GPS removed as a side effect

  The canvas holds pixels, not metadata, so re-encoding drops the lot. That removes the GPS coordinates phones embed by default, which is the main privacy risk in sharing a photograph — and it removes the copyright and camera fields too, which is worth knowing in the other direction.

• Files that got bigger are reported as bigger

  Converting a flat graphic to a lossy format, or a small PNG to JPEG where the overhead exceeds the saving, produces a larger file. The per-file figure shows a positive number when that happens. A converter that only ever reports savings is not measuring anything.

1. 1

   Add every image at once

   Choose them, drop them anywhere on the page or paste them. There is no count to watch: each becomes a card, the queue converts one file at a time, and each card shows its result as it lands.

2. 2

   Pick WebP unless something downstream refuses it

   It is the default for a reason, and the exceptions are specific rather than general.

3. 3

   Resize on the way through if the images are oversized

   Open More options and cap the longest edge. Resizing is almost always a bigger saving than any quality setting, because area scales with the square of the dimension.

4. 4

   Check each card, then download

   Every card shows its size before and after; one that grew says “larger” in red. Keep the originals for those, then take the rest with Download all as one .zip, or each with its own Download.

• How much PNG to WebP saves, measured on eleven imagesPNG to WebP at quality 0.82 in Chromium: photographs shrank 92% to 97%, a flat logo 69%, and icons under 128 px grew — up to 116% at 16 px.

• No AVIF output. No browser can encode AVIF from a canvas — decoding is widely supported and routinely confused with it. A WebAssembly encoder would cost roughly a megabyte of download and a broader Content-Security-Policy for a format WebP largely covers.
• Canvases are capped at 8,192 pixels a side and about 16.7 million pixels in total, in every browser, because that is the oldest iPhones’ ceiling. Oversized images are scaled to fit, and the card shows the size they came out at, rather than the blank image a canvas hands back past the ceiling.