A GIF is an image file that can contain a sequence of frames, so it plays as a short, silent, looping animation. CompuServe introduced the format in 1987, and it survives today mostly as reaction clips, simple animated icons and email banners.
How a GIF animation is put together
Each frame in a GIF uses a palette of at most 256 colours. The image data is compressed with LZW, a lossless method that works well on flat areas and badly on gradients. The 1989 version of the format (GIF89a) added a frame delay value and a looping extension, which is what turned a still-image format into an animation one.
Transparency in GIF is all or nothing: one palette colour can be marked as invisible, but there are no partially see-through pixels. That is why GIF logos on a dark background often show a jagged pale fringe around curved edges.
And yes, people still argue about the pronunciation. Steve Wilhite, who created it, said it is pronounced with a soft G, like the peanut butter brand Jif.
Why animated GIFs are so heavy
A GIF stores every frame as a full picture with only basic tricks for reusing unchanged areas. A few seconds of screen recording can easily be bigger than the same clip as an MP4 or WebM video, which uses modern motion compression. Platforms like Giphy and many social networks quietly convert uploaded GIFs into video files for exactly this reason, even though users still call them GIFs.
Swapping a demo GIF for a video
A software consultant adds a 10-second product demo GIF to the homepage hero. On mobile data it takes a long time to appear, and the 256-colour limit makes the interface look grainy. Replacing it with a muted, autoplaying, looping MP4 using the video element looks sharper and loads much faster, while behaving the same for visitors.
When GIF still makes sense
GIF remains useful in email, because many email clients will not play embedded video but will animate a GIF. Outlook desktop is a known exception that shows only the first frame, so put the key message there. On a website, an animated WebP or a short video is almost always the better tool, and for still graphics PNG beats GIF in every way.
Common GIF mistakes
- Using a long GIF as a hero. It eats bandwidth and delays the page.
- Converting photos to GIF. Reducing a photo to 256 colours causes banding and speckled dithering.
- Animations with no way to stop. Flashing or endlessly moving content distracts some users and can trigger problems for people with vestibular or seizure conditions.
- Leaving out alt text. Describe what the animation shows for screen reader users.
Related terms
- WebP: supports animation at smaller sizes.
- PNG: the better format for still graphics.
- Alt text: describes the animation for people who cannot see it.
- Lazy loading: keeps off-screen animations from loading early.