JPG vs PNG: which format should you use?

The short answer

• Photos: JPG. Smaller files, and the losses are invisible at sensible quality.
• Screenshots, text, logos, charts and interface graphics: PNG. Edges stay sharp and colours stay exact.
• Anything that needs a transparent background: PNG, or WebP and AVIF on the web. JPG cannot store transparency.

How they differ

JPG (JPEG, from 1992) is lossy. It splits the image into small blocks and discards fine detail and colour information the eye is least sensitive to. That is why photos shrink so well, and why sharp lines and text get fuzzy halos and blocky artifacts when compression is pushed too far.

PNG (from 1996) is lossless and supports full alpha transparency. Flat areas of colour compress very well, but photographic detail does not, so photos saved as PNG are often 3 to 10 times larger than as JPG.

Converting PNG to JPG

Converting a photo from PNG to JPG usually cuts the size dramatically. Two things to watch:

• Transparent areas have to become a solid colour. PNG to JPG fills them with white by default, and you can choose another colour.
• Screenshots and graphics can look worse as JPG and may even get larger. If a PNG is big because it is a screenshot, compress it as a PNG instead.

Converting JPG to PNG

Saving a JPG as PNG does not restore any quality. The artifacts already in the JPG are preserved exactly, and the file usually gets several times larger. It makes sense when the next step needs a lossless format, for example so repeated edits do not add new JPEG artifacts, or when you are about to add transparency.

What about the newer formats?

On websites, WebP and AVIF can replace both. They offer lossy and lossless compression and support transparency at smaller sizes. For email, documents, printing and upload forms, JPG and PNG remain the safest choice because practically everything opens them.