GIF Optimiser

How to use the gif optimiser

1. Choose a GIF.
2. Lower the colour count, drop frames, or both.
3. Rebuild, check the reported change, and download if it improved.

About this tool

A GIF's size comes from three things: its dimensions, its frame count and its palette. This tool addresses the second and third; the resizer and cropper address the first, and they are usually the bigger win — halving the dimensions removes three quarters of the pixels, which no palette reduction can match.

Colour reduction is the gentler lever. A GIF holds at most 256 colours already, and most animations look unchanged at 128 or even 64 — flat artwork and screen recordings particularly, since they contain far fewer distinct colours than the palette allows. Photographic content degrades visibly much sooner, and banding in gradients is the first thing to appear.

Dropping frames is the blunter one and often the most effective, because frame count multiplies everything else. Half the frames is close to half the file, and for a screen recording at a high frame rate the result is frequently indistinguishable.

One honest caveat: re-encoding a GIF that is already well optimised can make it slightly larger, because the encoder here is not the one that made it. The change is reported after rebuilding rather than assumed, so you can see whether it was worth it.

Browsers display animated GIFs and offer no way to read their frames — draw one to a canvas and you get the first frame only. The GIF is therefore decoded by an implementation on this page: header, colour table, LZW-compressed image data, and the disposal model that composes each frame onto the last. That last part is the one usually skipped, and skipping it is why frames come out of some tools with holes in them, since most GIFs store only the pixels that changed between frames.

Common uses

• Getting a GIF under an upload size limit.
• Reducing a screen recording that is unnecessarily large.
• Trading a little quality for a much smaller file.

Frequently asked questions

What reduces a GIF's size most?

Dimensions first — halving them removes three quarters of the pixels. Then frame count, then colours, which is the gentlest of the three.

How few colours can I use?

Flat artwork and screen recordings usually survive 64 or even 32 unchanged. Photographic content bands visibly much sooner.

Why did my file get bigger?

Because a well-optimised GIF re-encoded by a different encoder can grow. The change is reported so you can see it rather than discovering it later.