Convert GIF to ICO

A GIF of a logo is almost never the logo. It is an export, made once for a web page at whatever size that page needed, reduced to 256 colours and often scaled down from something larger. Somewhere there is usually an original — an Illustrator file, an SVG, a high-resolution PNG in a brand folder.

It is worth five minutes of looking, because an icon made from vector artwork can be redrawn at 16 pixels with the strokes thickened so it stays legible, and an icon made from a 120-pixel GIF cannot. If the search comes up empty, which it often does on a site nobody has owned for a decade, this conversion is the sensible fallback and the rest of this page is about making it work.

ICO is a container. Microsoft designed it in 1985 to hold a set of the same picture at different sizes, so that Windows could pick 16 pixels for a list, 32 for a desktop and 256 for a preview without scaling anything. That is still its main advantage over any other icon format, and it is the reason a format from 1985 is still being requested by browsers in 2026.

What this conversion writes is that set. The directory carries one entry per size you chose — three by default, at 48, 32 and 16 pixels, each a real PNG made at that size and listed largest first. Nothing downstream has to guess: a browser drawing a 16-pixel tab reads the directory and takes the 16. For a GIF that is a better outcome than it sounds, because a small legacy logo scaled up to 256 and then squeezed back down by a browser is exactly the route that turns an old mark into a grey smear.

If the GIF’s longest edge is over 256 pixels, the picture is scaled down until it is exactly 256 and the shorter edge follows proportionally. Each icon entry is then made from that, so with the default set a 400-pixel logo becomes a 48, a 32 and a 16. A GIF smaller than the sizes you asked for is enlarged to fill them, which is the one way to make the result worse than the source: a 90-pixel logo converted with "256 px only" is a 90-pixel logo blown up.

The cap is the format’s, not a policy: an ICO directory entry stores each dimension in a single byte, so 256 is written as zero because 256 does not fit in a byte and zero is the specification’s way of spelling it. Anything larger has nowhere to be recorded, which is why every icon toolchain stops at the same number.

Every entry written here is square, because that is what an icon is. A wordmark GIF that is 240 by 64 keeps its proportions and is centred on the square at the largest scale that fits, with transparency filling the bands above and below. Nothing is squashed, which is the important half — a stretched logo is recognisable as a mistake from across a room.

The other half still costs you. A 240 by 64 mark centred in a 16-pixel square is drawn about four pixels tall, which is nothing, and the transparent bands are wasted icon. So crop to a square first, and crop rather than scale: take the initial, the symbol or the monogram, centre it, and leave only a small margin so the mark uses the frame it is given.

Each entry in the directory is a PNG. The format also permits a raw bitmap payload — that is what it originally meant — but every Windows since Vista reads a PNG inside an ICO, the file is a fraction of the size, and the alpha channel is proper rather than a one-bit mask. That choice is why the icon looks correct on a dark tab bar.

It is also why there is no quality setting on this page. PNG is lossless and has nothing to turn down, so a slider here would move and change nothing; it is not offered, which is the only honest arrangement. The pleasant consequence is that several small entries cost less than one large one: three PNGs at 48, 32 and 16 pixels of a flat logo came to 1,062 bytes against 2,229 for the single 256 this page used to write. A better favicon and a smaller file.

GIF transparency is a single palette entry marked as see-through. A pixel is either fully transparent or fully opaque; there is nothing in between, and the antialiasing around a logo’s curves was baked against whatever background the GIF was designed to sit on.

Scaled down to 32 pixels, that shows. The pale halo of a logo that was antialiased against white will still be pale against a dark browser theme, which reads as a dirty outline rather than as a clean mark. There is no setting that removes it, because the information about what those edge pixels should have been was discarded when the GIF was made. If the halo is bad enough to notice, the fix is to redraw from the source rather than to convert differently.

The palette limit that makes GIF a poor photographic format is close to irrelevant here. Logos are flat colour by design — two or three fills, a hard edge, no gradients — and 256 entries is far more than that needs, so the GIF is very likely holding the mark exactly as it was drawn.

The pixel dimensions are the real constraint. An icon is judged at 16 and 32 pixels, and what matters there is whether the shapes are still distinguishable: a thin serif disappears, a two-word wordmark disappears, a solid geometric symbol survives. Test by looking at the actual tab rather than at the file, which is the mistake nearly everybody makes on their first attempt.

Modern practice is a set of PNGs and an SVG icon declared in the page head, and there are good arguments for it. But the file at the root path is still requested by browsers that find no declaration, by feed readers, by link previews and by a long tail of tools that were written when it was the only mechanism. It costs one file to satisfy all of them.

So the pragmatic arrangement is both: an ICO at the root as the universal fallback, and whatever modern declarations the site’s templates support alongside it. Converting the GIF here gives you the first half in one step, and it is the half that keeps working when nothing else is configured.

The GIF is decoded by the browser, the picture is encoded as a PNG, and the icon directory is written around it in JavaScript in the same tab. Nothing reaches a server, there is no account, and there is no watermark or sign-up step between the conversion and the download.

For a logo that is often a small point and occasionally a real one: brand assets under embargo, an internal tool’s mark, a client’s artwork you were sent under an agreement. None of it needs to pass through anybody else to become an icon.