JPG vs PNG: which format should you actually use?

The usual advice — "PNG is higher quality, JPG is smaller" — is true and almost useless. Both formats can look perfect or terrible depending on what you put into them.

They compress in fundamentally different ways

JPG chops the image into 8×8 blocks and describes each one as a sum of wave patterns, then throws away the patterns your eye is least sensitive to. This works beautifully on photographs, where colour changes gradually. It works terribly on hard edges, where those discarded high-frequency patterns are exactly the detail that made the edge sharp.

PNG looks for repetition instead. A row of identical pixels compresses to almost nothing. This makes it superb on flat colour and useless on photographs, where practically no two adjacent pixels are the same.

The five-second decision

Ask one question: does the image have large areas of exactly the same colour?

• Yes — logos, icons, screenshots, diagrams, charts, anything with text: use PNG.
• No — photographs, gradients, anything from a camera: use JPG.

Where transparency comes in

If any part of the image needs to be see-through, the decision is already made: JPG cannot do it. PNG can, including the partial transparency along antialiased edges that makes a logo sit cleanly on any background.

The honest answer for the web in 2026

For anything going on a web page, WebP beats both. It handles photographs better than JPG, flat graphics better than PNG, and supports transparency. Browser support has been universal for years.

The reason JPG and PNG still matter is everything outside a browser: print shops, older desktop software, upload forms that have not been touched since 2015. That is a compatibility question, not a quality one.