Convert PNG to JPEG

Why a PNG photograph is so heavy

PNG is lossless, which means it stores the picture exactly rather than approximating it. For a logo or a screenshot of text that is the right trade: hard edges stay hard and flat colour compresses to almost nothing.

A photograph has no flat colour and no hard edges. Every pixel of sky is slightly different from its neighbour, so lossless storage has nothing to work with and the file stays enormous. The same photograph as a JPEG is routinely a tenth of the size and nobody can see the difference. That is the conversion this page is for.

Transparency is flattened onto white

JPEG has no transparency. It cannot store it, so it has to become something, and here it becomes white.

This is worth knowing before you convert a logo. A white mark on a transparent background will convert into a white mark on white, which is invisible. If your PNG has transparency you want to keep, do not convert it to JPEG at all: use WebP, which is both much smaller than PNG and keeps the alpha channel.

When to keep the PNG

• Anything with transparency, for the reason above.
• Logos, icons and diagrams. Flat colour and hard edges are what PNG is good at, and JPEG makes a mess of them: the compression smears a halo around every sharp edge.
• Screenshots containing text. Small lettering is exactly the high-contrast detail JPEG handles worst, and the result looks fuzzy at the size people actually read it.
• A master you will edit again. JPEG is lossy and the loss compounds every time you re-save. Keep the PNG and export a JPEG from it.

Or skip JPEG and use WebP

If the file is going onto a web page rather than into somebody’s inbox, WebP beats JPEG by 14 to 20% on our own photographs, and AVIF beats it by 57 to 58%. Both keep transparency, which JPEG cannot. The full comparison has the numbers.

JPEG is still the right answer when the file is going somewhere old or unknown. Every piece of software made in the last thirty years reads one.