PNG Image Format – History, Features and Advantages

PNG stands for Portable Network Graphics. PNG is a type of image format like other image formats such as JPEG, GIF, and TIFF. PNG is commonly pronounced as P-N-G whereas some people also call it “ping”. PNG is used for lossless image compression and is a raster graphics file format. PNG supports all the true colors and is widely used for image transferring on the World Wide Web. PNG is not suitable for printing purposes as it does not support the CMYK color scheme. PNG images have a file extension PNG or png.

1. History and Purpose
2. Versions
3. PNG Features
4. Advantages & disadvantages of PNG Format
5. When to use PNGs
6. Open and edit PNG files

History and Purpose

In the year 1995, Unisys Corporation enforced a patent on the Lempel Ziv Welch algorithm which resulted in the patent on GIF file format on the companies which uses these images for profit generation.

Another drawback of GIF file format was that it could only display 256 colors while at that time graphic hardware used in computers could support a larger color resolution. Keeping in view these drawbacks of GIF images, work on PNG started. In 1995 at a discussion on the image formats, Oliver Fromme who is the developer of famous DOS JPEG viewer QPEG suggested the name for this new image format as PING.

Versions

Till now there have been 5 major versions of PNG. The first iteration of the PNG file format was released in October 1996 by the World Wide Web Consortium (W3C).

On October 14, 1997, the Internet Assigned Numbers Authority (IANA) approved “image/png” making it one of the official Internet Media Types. Image/png had officially joined image/gif and image/jpeg as recognized image formats.

Further progress saw the release of version 1.1 in December 1998 and version1.2 in August 1999. In 2003, PNG became an International Standard and in March 2004, the standard version was released.

This table gives a summary of the PNG versions and their release dates.

PNG Features

Cross-platform support means PNG files correctly display on PCs, Macs, Android, and iOS platforms.

PNGs support 24-bit RGB, 32-bit RGBA, and greyscale color palettes. The 24-bit color (true color) is capable of millions of color combinations. The 32-bit RGBA has an alpha channel that allows for additional color gradients and transparencies with massive color combinations.

PNG images are smaller and load faster than equivalent GIFs or RGB TIFF. Indexed color GIFs are about 30% larger than indexed-color PNGs, while true-color RGB TIFF files are on average 40% larger. PNGs also feature advanced interlacing schemes which means you can preview a PNG file with just 1/64th of the data loaded. For interlaced GIFs, the image data that needs loading for a preview is at least 8 times slower.

Support for web searches and indexing – you can have keywords and other text details added to the PNG file. With these keywords, a search tool can easily find the right image via search engines.

Advantages of PNG Format

• Uses a lossless image compression technique, hence no information is lost and the image is retrieved keeping the same quality.
• Supports all the true colors, unlike the contemporary GIF format which only supports 256 colors.
• Alpha channel support in PNG images allows transparency of the file format which is not possible with other file formats.

Disadvantages of PNG Format

• The PNG image is usually larger in size as compared to the traditional GIFF because it is a lossless image format. However, if PNG is saved with a 256 color scheme, its size is lesser as compared to GIF.
• PNG format doesn’t support animations and similar graphics and for this purpose, a variation of the PNG format, MNG (Multiple Network Graphics) and APNG (Animated Portable Network Graphics) are used.

When to use PNGs

The PNG image format works when we download web images, receive digital photos as email attachments or when we save screenshot images. Graphics professionals also go for PNG files, especially when handling web graphics that involve transparent backgrounds.

PNG is best when dealing with true-color images that cannot work well with JPEG compression. An example is when you are using raytraced images. If you also do a lot of web design, PNG is for you as it allows for transparent backgrounds. Designing a logo is, for instance, easy when using .png file images as you can effortlessly position images over pictures, color patterns or other color backgrounds.

Use PNG when your illustrations have limited colors because these types of image files work best where there’s a small color palette.

You can also go for PNG when all you need is a small file for web graphics. PNG image files can be compressed to an extremely small size.

Open and edit PNG files

You can open PNG images using several programs, available freely and commercially. Almost any image or video editor can help you open PNG images. Web browsers and software applications like Windows and macOS also support PNG files.

Use any of Firefox, Chrome, Opera or Safari browsers to open .png image types. Paint 3D, Adobe PhotoShop and XnView are some of the most commonly used apps for opening PNG files.

If you want, you can convert a PNG file into JPG, BMP, or GIF image. Open your file image and “save as” by choosing the file format to which you wish to convert the file.

You can also convert PNG to PDF using PDF.co converter.

Note: If you stretch a PNG file into a larger file, it becomes grainy, visibly distorting the resultant image. To avoid having pixilated photos, always save your PNG files as they are. You could shrink or compress them (as opposed to enlarging).

   

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