Convert PNG to JPG

What you gain and what you give up

PNG stores images losslessly, which makes it superb for graphics but heavy for photographs. JPG takes the opposite approach: it discards fine detail the eye is unlikely to miss and compresses the rest hard. For a photo, the JPG is typically several times smaller than the PNG, and at a sensible quality setting the difference is usually hard to see.

The trade-off is that JPG is always lossy. Once detail is discarded it is gone for good, and converting the JPG back to PNG later will not bring it back. Keep your original PNG if there is any chance you will need the full-quality version again.

The size difference comes from how each format compresses. PNG works by finding predictable, repeating patterns of exact pixel values, which flat colours have plenty of and camera noise has almost none. JPG instead approximates small blocks of the image, which suits the gradual tones of a photograph but struggles with abrupt edges. That is why the same conversion can shrink a holiday photo dramatically and barely help a logo.

PNG vs JPG compared

Good candidates for JPG, and poor ones

The images that benefit most are photographs that happen to be stored as PNG: pictures exported from an editor that defaults to PNG, photos pasted into a design tool and saved again, or camera images that were converted to PNG somewhere along the way. These shrink dramatically and become much easier to email or upload where file size limits apply.

Be more cautious with:

• Screenshots of apps and web pages, where small text can turn fuzzy;
• Logos, icons and diagrams, whose flat colours and sharp lines show JPG artefacts readily and often compress well as PNG anyway;
• Anything that needs a transparent background in its final location.

If you want a smaller file but cannot give up transparency, convert PNG to WebP instead. WebP keeps the alpha channel and is usually compact.

Choosing a background colour for transparency

Because JPG cannot store transparency, every transparent pixel in your PNG is filled with the background colour you set before converting. White is the default and works well for documents, printed pages and most emails.

For anything else, match the destination. A logo destined for a dark website header should get that header's exact colour; otherwise it will sit inside a visible white rectangle. Most design tools and website themes list their background as a hex value, such as #1F2937, which you can copy straight into the colour setting. The fill is permanent, too. The JPG keeps no record of which areas were transparent, so hold on to the PNG if you might need the cut-out again.

Settings that keep JPGs small and clean

• Quality: the default of 90 keeps photos clean. For everyday sharing, 80 to 90 is a sensible range; if you must convert a screenshot, stay at 90 or above to protect the text.
• Dimensions: a full-resolution image is often far larger than an email or web form needs. Fitting it within a maximum width or height reduces the file more than any quality setting, without distorting it.
• Convert once: export your JPG from the PNG master each time, rather than editing and re-saving a JPG, which loses a little more quality with every save.
• Metadata: EXIF details such as GPS position and capture date are not copied into the JPG.
• Colour: output is converted to sRGB, so artwork made in a wide-gamut colour space may look slightly less saturated.
• Animated PNGs: JPG has no animation, so only the first frame of an APNG is converted, and you will see a warning.
• Batches: convert up to 10 PNGs in one go and download them together as a ZIP, which is handy when a whole folder of exports needs shrinking.