PNG or JPG: which format should you choose?

Two formats, two logics

PNG is lossless: every pixel is preserved exactly, including its transparency level. It is very efficient on flat colour, screenshots, logos and illustrations. On a photograph its size climbs quickly.

JPG is lossy: the encoder simplifies the image to reduce size. It excels on photographs and gradients, but it has no transparency and handles repeated saves poorly.

When to keep PNG

• Logos and interface graphics: edges stay crisp.
• Screenshots containing text: no artefacts around the letters.
• Images edited several times: no cumulative loss.
• Anything that must stay transparent.

When to switch to JPG

• A photograph for the web or for sending by email.
• A very detailed visual where a reasonable size matters more than absolute precision.
• An image that does not need transparency.

What a conversion really changes

Converting PNG to JPG is more than renaming the extension: the pixels are re-encoded. Transparent areas are composited onto a background colour, and the chosen quality decides how much detail survives.

The other way round, converting JPG to PNG restores no lost detail. The file becomes lossless for the pixels it already has, which is enough to retouch an image without degrading it further.

Our practical rule

Crisp text, flat colour or transparency: PNG. A photograph to share: JPG. If you are unsure, convert a copy, compare the two real sizes the tool reports, then keep the original.