PNG (Portable Network Graphics) is an image file format that stores pictures without throwing any detail away. It can also have a transparent background, so a logo saved as PNG sits cleanly on any colour. Files end in .png.
How PNG stores an image without losing quality
PNG was created in the mid-1990s as a patent-free replacement for GIF and is now a W3C and ISO standard. It records the colour of every pixel, then shrinks the data with DEFLATE compression, the same family of compression used in ZIP files. Because that compression is lossless, opening and re-saving a PNG a hundred times gives you the identical image each time.
Each pixel can carry an alpha channel, a fourth value that says how see-through it is. That allows soft, partially transparent edges such as drop shadows, not just fully on or off transparency. PNG supports full 24-bit colour plus alpha, and also smaller palette modes with up to 256 colours for simple graphics.
Where PNG shines and where it struggles
PNG compresses areas of flat colour and sharp edges very well, which is why screenshots, diagrams, icons and logos with text stay crisp. Photographs are the opposite case. A camera photo has subtle noise in almost every pixel, so lossless compression has little to remove, and the same photo saved as PNG is often several times larger than a good-quality JPEG.
Example: a bakery owner exports the shop logo from Canva as PNG with a transparent background, and it looks sharp on both the white header and the dark footer. She then exports a 4000-pixel-wide photo of a cake as PNG too, and it weighs in at many megabytes and slows the homepage. The logo was the right call; the cake photo should have been JPEG or WebP.
When PNG matters for a small-business site
Use PNG for logos when you do not have an SVG version, for screenshots of software, for charts and for anything with small text that must stay readable. For photos and large hero images, a lossy format will load much faster. Modern browsers also accept WebP, which does lossless compression with transparency at smaller sizes than PNG in most cases.
Common PNG mistakes
- Saving photographs as PNG. The file balloons in size for no visible gain.
- Uploading the original huge dimensions. A 3000-pixel PNG shown at 300 pixels wide still downloads every pixel.
- Using a raster PNG where a vector would do. Simple logos and icons are usually smaller and sharper at any size as SVG.
- Flattening transparency by accident. Some editors fill the background white on export; check the setting before uploading.