Portable Network Graphics facts for kids
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A PNG image with an 8-bit transparency channel, overlaid onto a checkered background, typically used in graphics software to indicate transparency
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| Filename extension |
.png
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|---|---|
| Internet media type |
image/png
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| Type code | PNGf PNG |
| Uniform Type Identifier (UTI) | public.png |
| Magic number | 89 50 4e 47 0d 0a 1a 0a |
| Developed by | PNG Development Group (donated to W3C) |
| Initial release | 1 October 1996 |
| Type of format | Lossless bitmap image format |
| Extended to | APNG, JNG and MNG |
| Standard | ISO/IEC 15948, IETF RFC 2083 |
| Free format? | Yes |
Portable Network Graphics, often called PNG, is a special way to save pictures on computers. It's a file format that keeps all the details of an image without losing any quality. Think of it like saving a drawing without any smudges or faded colors! PNG was made to be a better and free alternative to an older format called GIF.
PNG files are great for images on the Internet. They are designed to transfer pictures quickly and clearly online. This format is not usually used for professional printing, as it focuses on screen display.
Contents
What Makes PNG Images Special?
PNG images can handle many different types of colors. They support images with a limited set of colors, like a palette of 24-bit RGB colors. They also work with grayscale images, which are just shades of gray.
Transparency in PNG
One cool feature of PNG is its ability to have transparency. This means parts of the image can be see-through. Imagine a sticker that you can place on any background, and it blends in perfectly. This is possible because PNG uses something called an "alpha channel."
How PNG Files Are Built
A PNG file holds a single image. It's built using small parts called "chunks." These chunks store the actual picture information, like the colors of each tiny dot (pixel). They also hold other details, such as text comments or checks to make sure the image hasn't been damaged.
How to Spot a PNG File
PNG files almost always end with the file extension `.png` or `.PNG`. When you see a file named `picture.png`, you know it's a Portable Network Graphics image.
This format became an official standard in March 1997. It was later recognized as an ISO/IEC standard in 2004. This means it's a widely accepted and reliable way to save images.
Images for kids
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The PNG image PNG-Gradient.png viewed with a hex editor application for Ubuntu.
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A demonstration of the colour depth in a PNG file, in bits per channel. Left: 8 bits, Right: 16 bits.
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Example with several types of image content
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PNG demo heatmap Banana.png
Representation of bit cost per pixel for above PNG file (red=expensive, blue=cheap)
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A PNG with 256 colors, which is only 251 bytes large with pre-filter.
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An illustration of Adam7 interlacing over a 16×16 image.
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An APNG (animated PNG) file (displays as static image in some web browsers)
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Composite image comparing lossy compression in JPEG with lossless compression in PNG: the JPEG artifacts can be easily visible in the background of this kind of image data, where the PNG image has solid color.
See also
In Spanish: Portable Network Graphics para niños
