GIF

What is a GIF?

GIF has two different meanings nowadays: originally, GIF was the name of a common old image format (file extension: .gif) which the PNG format sought to replace completely by having smaller file sizes with lossless quality, but failed to do so due to PNG not supporting animated images which GIF supported. For a long while, GIF images were the only way to embed animated graphics in web pages, and many online communities, such as Tumblr and Imgur, prided themselves in their vast galleries of user-created GIFs, until users started creating GIFs out of scenes from movies and series, as if GIF was a video format, which it definitely wasn't. A single second of video at even small resolutions could easily become larger than 1 megabyte, and still have terrible quality since the format is only supports 256 colors per frame (i.e. is 8 bpp). Imgur then launched something called "GIF Video," which was actually a MP4 video that has a .gifv file extension instead of .mp4. The key differences in the GIF video were that they looped by default, something GIFs did but videos generally did not do; they had no audio, they were mute, just like the animated images they were based on; and they were extremely smaller and higher quality than their GIF counterparts, because it was an actual video format, allowing users to plaster Imgur with minute-long short videos. From then on, we got another video format for the web, two, in fact: WebM (web movie) and WebP (web picture). The WebP files can be animated, unlike PNG. Both animated WebP and WebM video use the same video format underneath, which is extremely important because it's an open format, allowing open web browsers to support without requiring proprietary decoders. This solved the video support problem for web browsers. Alongside this, HTML5 included a <video> tag which made it easy for web developers to embed WebMs in their web pages, solving the web video problem for everybody. This <video> tag has three attributes: autoplay, mute, and loop. As it would be extremely annoying, web browsers generally do not allow a video to play automatically if it has sound, but they will allow it if the video is mute. This meant that a WebM in a <video> tag could finally do what a GIF in an <img> tag used to do. Nowadays, most of the time you hear about "GIFs" you aren't hearing about the old GIF format, but about WebMs displayed on webpages without sound, looped, and auto-playing. Somehow, the GIF legacy survived to this day, although from now on, many people will call these WebMs what they are: WebMs.

For an example of WebMs being used as GIFs, the subreddit named /r/HighQualityGIFs.