PNG to JPG converter

What happens to your picture

A PNG stores every pixel exactly. A JPG stores an approximation that the eye reads as the same picture, which is why it is so much smaller for photos. The converter decodes your PNG, paints it onto a background of the colour you chose, and encodes the result with MozJPEG, the JPEG encoder Mozilla built to get smaller files out of the format. Files start converting as soon as you drop or paste them, and a batch downloads as one ZIP.

How much smaller the JPG is

For photos the saving is large. We saved six test photos, each 2048 pixels wide, as lossless PNG and as JPG with the same encoder and settings this page uses:

Quality 90 keeps photos very close to the original. Quality 75 to 85 is enough for most photos you send or upload: on these photos, 85 made files about 40 percent smaller than 90, and 75 about 60 percent smaller. Our article on JPEG quality settings shows what each step of the slider changes, with pictures.

When you should keep the PNG

Screenshots, logos, charts and anything with text are the opposite case. They have flat colour and sharp edges, which PNG stores efficiently and JPG does not. A 1600 by 1000 pixel chart we tested was 43.5 KB as PNG, 42.5 KB as JPG at quality 75, with grey halos around the letters, and 75.9 KB as JPG at quality 90. Converting it made the file no smaller and the text slightly blurred.

If a form or a website only accepts JPG, convert anyway and keep the quality at 90 or more so text stays readable. Otherwise keep the PNG, or try PNG to WebP, which shrinks graphics without halos.

Transparency and the fill colour

JPG has no transparency. Every see-through pixel is painted with the fill colour, white unless you pick another. Half-transparent pixels, such as the soft edge of a logo or a drop shadow, are blended with that colour, so the edge is drawn for one background only. If the JPG will sit on a dark page, choose the page colour as the fill before converting, or the logo will show a pale fringe. If you need the transparency itself, keep the PNG or use WebP.

Making the picture smaller as you convert

The longest side setting caps large pictures at 3840, 2560, 1920, 1280 or 800 pixels and never enlarges small ones. Pixels count for more than quality: a photo at half the width has a quarter of the pixels, and its file shrinks almost as much. Most websites and chat apps show photos at 1920 pixels or less, so capping there removes detail nobody would see. For an exact width and height, use resize image.

If the result looks wrong

• The JPG is bigger than the PNG. The picture is a graphic or a screenshot rather than a photo. Keep the PNG, or lower the quality and check that the text is still sharp.
• A logo has a white box around it. That box was transparent in the PNG. Convert again with the colour of the background it will sit on.
• Skies or gradients look banded or blocky. Raise the quality to 90 or more; smooth areas show JPG compression first.
• An animated GIF became a still picture. A JPG holds one picture, so only the first frame is converted.

How we tested. Six CC0 photos scaled to 2048 pixels wide, and a 1600 by 1000 pixel chart with text, encoded in Chrome with the MozJPEG and OxiPNG builds and settings of this converter. PNG sizes are lossless files after OxiPNG optimisation.