Editing GIF (section)

===PNG===
[[Portable Network Graphics]] (PNG) was designed as a replacement for GIF in order to avoid infringement of Unisys' patent on the LZW compression technique.<ref name="PNG" /> PNG offers better compression and more features than GIF,<ref name="png_fea">{{cite web |title=PNG versus GIF Compression |date=31 March 2007 |url=http://www.websiteoptimization.com/speed/tweak/png/ |access-date=8 June 2009 |url-status=live |archive-url=https://web.archive.org/web/20090715080828/http://www.websiteoptimization.com/speed/tweak/png/ |archive-date=15 July 2009}}</ref> animation being the only significant exception. PNG is more suitable than GIF in instances where true-color imaging and [[alpha transparency]] are required.

Although support for PNG format came slowly, new [[web browser]]s support PNG. Older versions of [[Internet Explorer]] do not support all features of PNG. Versions 6 and earlier do not support [[alpha channel]] transparency without using Microsoft-specific HTML extensions.<ref>{{cite web |title=AlphaImageLoader Filter |date=4 September 2012 |publisher=Microsoft |url=http://msdn.microsoft.com/en-us/library/ms532969(VS.85).aspx |access-date=26 May 2015 |archive-date=3 October 2014 |archive-url=https://web.archive.org/web/20141003214847/http://msdn.microsoft.com/en-us/library/ms532969(VS.85).aspx |url-status=live}}</ref> [[gamma correction|Gamma]] correction of PNG images was not supported before version 8, and the display of these images in earlier versions may have the wrong tint.<ref name="new_ie7">{{cite web |url= http://msdn.microsoft.com/en-us/library/ms649487%28VS.85%29.aspx |title= What's New in Internet Explorer 7 |work= [[MSDN]] |access-date= 6 March 2009 |archive-date= 1 March 2009 |archive-url= https://web.archive.org/web/20090301140032/http://msdn.microsoft.com/en-us/library/ms649487(VS.85).aspx |url-status= live }}<!--<on no gamma support--></ref>

For identical 8-bit (or lower) image data, PNG files are typically smaller than the equivalent GIFs, due to the more efficient compression techniques used in PNG encoding.<ref name="png_opt">{{cite web |title=PNG Image File Format |url=http://www.scantips.com/basics9p.html |access-date= 8 June 2009 |archive-url=https://web.archive.org/web/20090614110627/http://www.scantips.com/basics9p.html |archive-date=14 June 2009 |url-status=live}}</ref> Complete support for GIF is complicated chiefly by the complex canvas structure it allows, though this is what enables the compact animation features.