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GIF: universal animation, with 1980s limits

GIF is a 1980s format that survives because animated GIFs play everywhere — in browsers, chat apps and most email clients. It is limited to 256 colours per frame and on-or-off transparency, and animated GIFs are far larger than the same clip as video or animated WebP.

GIF at a glance

File extensions
.gif
MIME type
image/gif
Compression
Lossless (LZW) — but only after the image is reduced to a palette of at most 256 colours.
Transparency
One palette colour can be marked fully transparent. No partial transparency.
Animation
Yes, frame by frame, with per-frame delays and looping.
Colour
Up to 256 colours per frame, chosen from 24-bit colour.
Browser support
Every browser, and nearly every chat app and email client.
In ImageDoctor
Opens GIFs, but editing and converting use the first frame only, so animation is not kept. The Metadata Remover is the exception: it cleans GIFs without re-encoding, so every frame survives.

Why GIFs look grainy

A GIF frame can hold at most 256 distinct colours. A photograph has hundreds of thousands. To fit, the image is reduced to a palette and the missing shades are faked with dithering — a pattern of dots that averages out to the right colour from a distance. That is the speckled, grainy look of photo GIFs, and why smooth gradients like skies turn into visible bands.

Technically GIF compression is lossless: it stores the palette-reduced image exactly. The loss happens in the step before — squeezing full colour into 256 — and it is often severe.

Transparency is all or nothing

GIF can mark one palette colour as transparent. A pixel is either fully see-through or fully solid, with nothing in between, so anti-aliased edges cannot blend into the background. Place a GIF logo on a colour it wasn't made for and you see a jagged fringe of the old background around it. PNG and WebP store partial transparency and don't have this problem.

Why animated GIFs are so big

GIF compresses each frame more or less on its own. Video formats describe most frames as small changes from the one before, which is enormously more efficient. The result is that a few seconds of screen recording as a GIF is commonly several times — sometimes many times — larger than the same clip as an MP4 or an animated WebP, and looks worse.

When to use GIF

  • Short, simple animations that must play everywhere, including email clients that won't play video or animated WebP.
  • Tiny graphics with a handful of flat colours, for systems that only accept GIF.

When not to

  • Photographs. Use JPEG or WebP.
  • Logos and graphics with soft edges or transparency. Use PNG, WebP or SVG.
  • Long or detailed animations on a website. A muted, looping video or an animated WebP is far smaller.

What ImageDoctor does with GIFs

Browser canvases can only draw one frame of an animated GIF at a time, so the resizer, compressor, converter and editors all work on the first frame and save a still image — the converter and the Image Analyzer both point this out. If you only need to remove hidden data from an animated GIF, the Metadata Remover cleans it without re-encoding, and the animation is kept.

Common questions

Not as an animation. The tools work on the first frame and save a still image. The Metadata Remover is the exception: it keeps every frame.

GIF is limited to 256 colours per frame, so photos and gradients are approximated with dithering — a dot pattern that shows up as grain or banding.

For still images, PNG or WebP (graphics) and JPEG or WebP (photos). For animation on a website, a looping video or animated WebP is much smaller.

Tools for GIF files

Image ConverterConvert between JPG, PNG, WebP and AVIF with control over quality, transparency and background colour.Image Metadata RemoverStrip EXIF, GPS and camera information before sharing, and compare what was removed.Image AnalyzerInspect dimensions, weight, transparency and colour, with practical suggestions for the web.

Keep reading

All image formats