PNG to JPG

Converting a PNG to JPG is usually about size. PNG stores images losslessly, which is excellent for screenshots and logos and wasteful for photographs — a photo saved as PNG is often several times larger than it needs to be, and converting it to JPG at high quality typically cuts it by seventy to ninety per cent with no visible difference.

There is one thing to know before you do it. JPG has no transparency, so any transparent area has to become something. Here it becomes white, which is right for most images but wrong for a logo intended to sit on a coloured background — that will gain a white box around it. If the transparency matters, keep the PNG.

The conversion is also lossy and permanent. JPEG works by discarding detail the eye is poor at noticing, so text and sharp edges suffer more than photographs do. A screenshot full of small text converted to JPG will look noticeably softer, which is why screenshots are better left as PNG.

The quality slider controls the trade directly. Ninety-two per cent is visually indistinguishable from the original for almost any photograph; below about fifty you start seeing blocky patches in smooth areas.

Everything runs on your device, so nothing is uploaded and there is no size limit beyond what your browser can hold.