About this converter

This site takes a PNG and writes a JPG. It does not take anything else and it does not write anything else.

Why one format pair gets its own domain

Because that pair asks a question no general converter answers out loud. JPEG has no alpha channel, so a decision has to be made about every transparent pixel, and almost every tool makes it silently. People find out when they open the file and see a black square, or a grey rim around a logo that did not have one before.

A converter that is about every format has to treat that decision as one case among many. A converter that is about this one pair can spend everything it has on it: the colour picked explicitly, previewed on the actual picture, with the fringe explained and repaired, and with an honest answer when the right move is not to convert at all.

What it will not grow into

• Other input formats. HEIC, WebP, AVIF, TIFF, BMP and GIF frames belong somewhere else, and the refusal here says where.
• A search for a file size in kilobytes. That is a different product with a different interface, and this one names it rather than imitating it.
• Background replacement. A matte is a flat fill under the whole frame, not a photograph behind a subject.
• Resizing as a goal. Dimensions only move here when a file is over the working limit and you agree to a lighter copy.

How it is built

A static export with no server behind it. The PNG is decoded by the browser, the composite runs on a canvas, and the JPEG is written by the same canvas. There is no model, no WebAssembly and no upload. A build audit fails the release if any module that can reach image data also references a network or storage API.

The one thing the browser will not let this page control is chroma subsampling: the encoder takes a type and a quality and no third argument. Rather than claim a setting it cannot set, the tool reads the sampling factors back out of the file that was written and prints those.

Who keeps it

It is one of a set of single-purpose image tools built on the same engineering and the same privacy posture, each with its own scope. The credit under the wordmark says so. It is a maker's mark rather than a network badge, and it is not a link.