PNG file format: what it is and how to use it

PNG (Portable Network Graphics) keeps images sharp with lossless compression and supports transparent backgrounds. Learn when to use it, how to open a PNG file and which format to choose instead.

Open PNG viewer Create a PNG

Free browser tools. Your images stay on your device.

  • Lossless qualityPreserves encoded pixels
  • TransparencySupports clear backgrounds
  • Widely supportedBrowsers and image editors

What is a PNG file?

A PNG file is a raster image: it stores a picture as a grid of pixels. Its lossless compression preserves the encoded pixel data, while optional alpha transparency allows clear backgrounds and smooth, partially transparent edges.

When should you use PNG?

  • Screenshots and diagrams: keep text, fine lines and flat colors crisp.
  • Logos, icons and overlays: preserve transparent backgrounds without a solid rectangle around the image.
  • Lossless image copies: save without adding compression artifacts. Resizing, editing or reducing the color palette can still change the image.

When is another format a better fit?

For photographs, JPG usually produces smaller files. For web delivery, WebP or AVIF can reduce file size while retaining transparency. PNG is pixel-based, so enlarging it can look blurry; a vector format such as SVG is better for artwork that needs to scale.

The short version: choose PNG for sharp graphics and lossless transparency, not automatically for every photo.

How to open a PNG file

Windows

Double-click the file to open it in Photos, or choose Open with → Paint to edit it.

macOS

Double-click the file to open it in Preview. Use File → Export to save a copy in another format.

In your browser

Drop the file into a browser tab, or use the dexrr PNG viewer. No installation needed.

Also opens in

  • Any web browser
  • GIMP
  • Adobe Photoshop
  • Paint.NET

View or convert PNG files

A quick preview or a new format. No install, no upload.

Open PNG viewer Preview and inspect image files Create a PNG Turn another image into a PNG PNG to JPG Smaller files for photos PNG to WebP Smaller for the web, keeps alpha PNG to AVIF Newest format, smallest files PNG to ICO Favicons for your website

PNG technical details

Full name
Portable Network Graphics
Extensions
.png
MIME type
image/png
Magic bytes
89 50 4E 47 0D 0A 1A 0A
Compression
Lossless
Developer
PNG Development Group / W3C
Specification
W3C PNG specification

PNG questions, answered

Is PNG better than JPG?

For screenshots, text and transparent graphics, PNG is often the better choice. For photographs, JPG usually gives a much smaller file at a similar visual quality. Neither is best for every image.

Are all PNG files transparent?

No. PNG supports transparency, but a file can still have a fully opaque white or colored background. Saving a JPG as PNG does not automatically remove its background.

Does PNG lose quality when saved?

PNG compression itself is lossless: it preserves the pixel data being encoded. Editing, resizing, color conversion or reducing the palette can change those pixels before the file is saved. Converting a JPG to PNG cannot restore detail already lost to JPG compression.

Why is my PNG file so large?

Large dimensions, photographic detail and noise can make lossless files large. Resize if you need fewer pixels, try lossless optimization, or export a JPG, WebP or AVIF copy. The best size depends on the image and export settings.

How do I convert a PNG to JPG or WebP?

Open the matching dexrr converter, choose your PNG and download the converted image. Use PNG to JPG for an opaque photo or PNG to WebP for web delivery with transparency. Conversion runs locally in your browser, without uploading your image.

Why will my PNG file not open?

The download may be incomplete, the file may be damaged, or its extension may not match its contents. Try another image viewer and download the original again. Renaming a file to .png does not convert it into a PNG image.