advantages PNG ïåðåä GIF
PNG implements an open, non-proprietary data compression algorithm that gives still better than GIF.
Unlike GIF with its maximum of 256 colors, PNG can store full-color images from 24 or even 48 bits per pixel.
PNG implements a much more efficient algorithm for interlaced (which in this case should have been called "by-pixel"). Suffice to say that the first pass, providing general information about the image in PNG is not one-eighth of the original file as a GIF, and only one-sixty-fourth - and yet recognizable to the picture when it is noticeably better.
PNG can store complete information about the transparency of each point of the image in the form of a so-called alpha channel. Each pixel PNG-file, regardless of its color and location may have any gradation of transparency - from zero (full netransparency) to completely invisible.
To smooth the differences in the brightness of displays that exist between different types of computers (and, respectively, between the images created by them), PNG can store in the source luminance factor of the display on which the image was created. This allows the program will scan before displaying adjust the brightness, adapting it to the characteristics of the video (so-called gamma correction).