Convert JPG to ICO
Two things go wrong when a favicon starts life as a JPEG, and both are worth knowing before you look at the result. The corners will be opaque, because JPEG cannot describe transparency. And a photograph at sixteen pixels is a colored smudge.
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What it does
- 16, 32 and 48 pixel frames in a single .ico file
- Works with any JPEG, whatever its dimensions
- Square output, since JPEG carries no transparency
- No watermark and no sign-up
How to use JPG to ICO
- 1
Crop it square first
Icons are square. A rectangular JPEG will be fitted into a square frame, so decide yourself what gets cropped rather than leaving it to the converter.
- 2
Add the JPG
Any size works. Larger is mildly better, since each icon frame is reduced from the source rather than from an already-reduced copy.
- 3
Convert and look at it small
Judge the result at actual size in a browser tab, not zoomed in. That is the only test that matters and it fails more often than people expect.
How it works
The JPEG is decoded and resized three times — to 16, 32 and 48 pixels — with each result fitted inside a square frame. The three are packed into one .ico container with a directory at the front describing them.
Every frame is produced from your original rather than from the frame above it. That matters more than it sounds: reducing 512 to 48 to 32 to 16 compounds the softening at each step, while going directly from the source each time keeps as much definition as the size allows.
The transparency problem, stated plainly
JPEG has no alpha channel and never has. Every pixel is opaque.
So a logo saved as a JPEG has already had its transparency replaced by a background color, usually white, and that color is now part of the image. It becomes part of the icon. On a browser tab with a light background a white square is nearly invisible and the result looks fine; on a dark theme it is a bright block around your mark.
There is no conversion setting for this. The information was discarded when the file became a JPEG, and the fix is upstream: get a PNG or an SVG.
Why photographs make poor icons
An icon is read at a glance, in a crowded strip, next to a dozen others. It works by shape, not by content.
At sixteen pixels a photograph averages down to a few blocks of color. Faces, buildings and products all become the same indistinct smudge — occasionally a pleasant one, never a recognizable one. This is why every icon you can actually identify is a simple mark: one shape, few colors, high contrast.
If the brand is a photograph, the icon should be something else — an initial, a symbol, a simplified silhouette.
When this conversion is the right call
A source that is already icon-like. A flat mark on a solid background, saved as a JPEG because that is what somebody sent you.
A quick placeholder. Something has to sit at /favicon.ico while the real one is designed, and an approximate icon beats a stream of 404s.
Legacy software wanting an .ico. Some Windows applications and installers still ask for one, and the source you have is a JPEG.
The better path, if you have the option
Start from a vector and every frame is drawn rather than shrunk. Failing that, start from a PNG and keep the transparency. JPEG is the worst of the three inputs for this job — it is lossy, it is opaque, and it is usually a copy of something better that still exists somewhere.
Examples
A simple high-contrast mark
This works because the source was already icon-shaped: one form, strong contrast, no fine detail. The square background is not a problem here since the artwork had a solid background anyway.
A photograph of a building
The conversion succeeds and the icon fails. At sixteen pixels a photograph has roughly 250 pixels to work with, which cannot describe a building — it describes an average color. This is not a converter limitation and no setting improves it.
Frequently asked questions
Why does my icon have a white or black square around it?
Because JPEG has no alpha channel. The format was designed for photographs, where every pixel is part of the picture, so there is no way to mark a pixel as transparent. Whatever filled the background in the JPEG fills the corners of the icon. To get a transparent icon you need a source that can express it — a PNG or an SVG.
Can I remove the background afterwards?
Not reliably, and not here. Removing a background means deciding which pixels are subject and which are not, which is an editing judgment rather than a conversion. Do it in an image editor first and save as PNG, then convert that — the transparency will survive from there.
My logo is a JPEG. What should I do?
Find the original. Logos are almost always drawn as vectors, and whoever designed it will have an SVG, AI or EPS file that produces a far better icon at every size. Converting from a JPEG means starting from a copy that has already been through lossy compression and lost its transparency.
Which sizes end up in the file?
16, 32 and 48 pixels — the sizes browsers and operating systems actually request for tabs, taskbars and shortcuts. Each is produced from your source image rather than from the next size up, so no frame inherits the softness of a previous reduction.
Further reading
- A Three-Size Favicon Was 15 KB and the Same Images Were 1.3 KBA favicon is the smallest image on a website and one of the larger files in its root directory, which is a strange thing to be true. The reason is that .ico is not a compressed format at all, and every extra size you add costs its full uncompressed weight.
- Which Favicon Sizes You Actually NeedMost favicon guides list a dozen sizes and explain none of them. Only a few are ever actually drawn, the rest are cargo from an older web, and knowing which is which turns an afternoon of exporting into about five minutes.