Png is a bitmap format of lossless compression algorithm, and its design purpose is to try to replace GIF and TIFF file formats, while adding some functions that GIF file formats do not have. PNG adopts lossless data compression algorithm derived from LZ77. Because of its high compression ratio and small file size, PNG is generally used in JAVA programs, web pages or S60 programs.
Development history:
In the early period of 1995, Unisys began to collect commercial fees according to the software patent of LZW data compression algorithm in GIF format. In order to avoid the influence of patent, PNG representing a single image and MNG representing animation are created at the same time.
1In August, 1999, Unisys further suspended the GIF patent free license for free software and non-commercial software developers, which made PNG format get more attention.
During the spread of PNG, it took many web browsers a long time to fully support PNG format. For example, the default Internet Explorer browser of Microsoft Windows did not support the translucent effect in PNG format until version 7.0.
Earlier versions (such as 6.0 SP 1) need to download Hotfix or additional script support provided by the website, which makes the PNG format not widely recognized.