PNG
full spelling ： Portable Network Graphics
The Portable Network Graphics (PNG) format was designed to be a better patent-free replacement for GIF format. PNG enable compression of images without any loss of quality, including high-resolution images.
PNG supports palette based (with a palette defined in terms of the 24 bit RGB colors), greyscale and RGB images. The file extension for PNG is .png.
One disadvantage of PNG is, not supported by older browsers but most of the current browsers have built in support for PNG format.