What is a PNG file?
A PNG is a picture file that keeps your image exactly as it is, and that can have a see-through background. That combination is why logos, icons, screenshots and diagrams are almost always PNGs, and why photographs usually are not.
PNG AT A GLANCE
- File extension
- .png
- Best for
- Logos, icons, screenshots
- Transparency
- Yes
- Quality loss
- None, ever
- File size
- Large
- Opens in
- Everything
The see-through background
A PNG can have parts that are completely see-through, so a logo saved as one sits cleanly on any colour of background instead of arriving in a white box.
This is the single most useful thing about the format, and it is why almost every logo you download from a company's press page comes as a PNG. Drop it onto a dark website, a coloured slide or a printed flyer and it simply works.
It is also where most people run into trouble. Save that logo as a JPG and the see-through part has to become a solid colour, because JPG has no way of storing "nothing here". Usually it turns white, and sometimes black, which is the reason a logo occasionally comes back looking like it is sitting on a dark rectangle. If you need to make that change, the PNG to JPG converter asks you which colour to use rather than guessing.
Nothing is ever lost
A PNG keeps every part of your picture perfectly, no matter how many times you open it, edit it and save it again. It never gets worse.
That is a real difference from a JPG. Each time a JPG is saved it quietly throws a little more away, and after enough rounds of editing and re-saving you can start to see it, particularly around text and hard edges. A PNG has no such problem, which is why designers keep their working files as PNGs and only convert at the end.
If you have a picture you expect to keep changing, keep a PNG of it. Convert copies for wherever they need to go, and leave the original alone.
Why PNG files are so large
Keeping everything costs room. A PNG holds your whole picture, so the file is a good deal heavier than the same image saved as a JPG or a WebP.
For a logo or an icon this barely matters. For a photograph it matters a lot: a photo saved as a PNG can be many times bigger than the same photo as a JPG, and you would not be able to tell them apart on screen. That is a lot of room and a lot of loading time for nothing.
It matters most on websites, where every picture is something a visitor has to wait for. This is why PNG has increasingly become a format people work in rather than publish in: keep the PNG, and put something lighter on the page. The PNG converter handles that in either direction.
When to choose PNG
Choose PNG for logos, icons, screenshots, diagrams and any picture that needs a see-through background or will be edited again later.
The pattern is straightforward once you see it. Pictures made of flat colour and sharp edges belong in PNG, because those are exactly the things other formats blur and smudge when they compress. Text in a screenshot stays crisp in a PNG and can go slightly fuzzy in a JPG.
Photographs are the other way round. They are made of soft, gradual detail, which is what JPG and WebP handle beautifully and what makes PNG so wasteful for them. If you are not sure which you have, ask whether the picture came from a camera. If it did, it is probably not a PNG job.
Questions people ask
Portable Network Graphics. It was created in the mid-1990s as a free alternative to GIF, and the name has stuck ever since.
You already can. Every web browser opens them, and so does the photo viewer that came with Windows, macOS, Android and iPhone. Nothing extra to install. A PNG that will not open is nearly always a damaged file rather than a missing program, and converting it will not repair it.
Because a PNG keeps every part of your picture perfectly, and that costs room. Formats like JPG and WebP get much smaller by quietly throwing away detail your eye is unlikely to miss. PNG never does that, which is exactly why people use it, and exactly why the files are heavy.
No. You can open and re-save a PNG as many times as you like and it stays exactly as it was. That is the main reason designers keep working files as PNGs rather than JPGs.
Yes, and it is what PNG is best known for. A logo saved as a PNG can sit on any colour of background without a white box around it, which is why almost every logo you download comes as one.
Usually not. A photo saved as a PNG can be many times larger than the same photo as a JPG or WebP, with no visible improvement to show for it. Keep PNG for logos, icons, screenshots and artwork with flat colour or sharp edges.