Most of us probably end up working on
favicon.ico as an afterthought, say, after you’ve finally shown the work to someone else and you see that the default icon is in use. Up to this point in the project you’ve likely considered this as work to do later.
For those who don’t know this already, this is the icon file which was displayed in Internet Explorer just to the left of the URL in the Location field. At one time it was only 16×16 pixels and enjoyed very little screen real estate, if you will. The file if present in your website’s root directory would be pulled by the browser. If you were an early website implementer like myself your discovery of the concept was when you were reading the website’s log files and kept seeing all the
"404 - file not found" errors from newer browsers which now expected it. So you likely created one to clean up your log files and shrugged it off.
Fast-forward to today and there are many popular browsers as well as platforms. Perhaps the biggest change has been the advent of touchscreen platforms that demand much larger buttons in which to invoke your shortcut. Bigger buttons means that our earlier one-size-fits-all approach no longer works; you can’t scale up a 16×16 icon graphic to the huge sizes required for a web TV platform.
Unfortunately, nobody came up with a consistent standard for this. What would have been nice would have been for everyone to populate a folder structure like this:
/icons/favicon.ico /icons/icon_16x16.png /icons/icon_32x32.png /icons/icon_256x256.png /icons/touch_256x256.png
And done. In this perfect world these would be the only icons and tiles available for the sum total of all browsers, all platforms, all devices. Period. If an operating system or browser needed something different, if would be necessary for that system to read the closest available graphic and to then create something else from it as required. It should not be up to the website designer to create what is seemingly required today.
Microsoft Internet Explorer
Microsoft originally specified
/favicon.ico to include one or more images. It could contain a 16×16, 32×32 and/or a 48×48 pixel version. Although the first size is good enough for the location field of the browser, if the end-user minimizes the browser then the 16×16 doesn’t seem big enough for the taskbar within Windows. Alternately, creating a shortcut to the website under some screen resolutions and settings requires an even bigger default icon, hence the three sizes.
Speaking of which, what format is a
.ico file anyway? Even though Microsoft has a tool within Visual Studio to combine multiple files into an
.ico file, you can actually get away with just renaming a
.png file to
favicon.ico and it will work fine with most browsers.
It sounds like these need
.png icons, one or more Apple Touch Icons, Windows 8 tile icons and a
Google TV wants an icon that’s 96×96 pixels.
Chrome wants an icon that’s 196×196 pixels.
Coast wants an icon that’s 228×228 pixels.
Apple Touch Icon
The iPhone/iPad collection of devices want an icon which is between 57×57 to 180×180 in size. The newer the device or in the presence of a Retina-technology screen, the higher the resolution it will need.
The odd thing here is that non-Apple browsers and platforms sometimes use the Apple-named icons because they’re usually better resolution than the default one.
Microsoft Metro Interface on Windows 8 and 10
You’d think that the 150×150 tile graphic would need to have that resolution but Microsoft recommends 270×270 for this one. Er, what?
And now, just when you thought this couldn’t be any more complicated,
/manifest.json might also be necessary and it serves a similar function as
Finding Some Sanity In All the Chaos
The current wisdom appears to involve providing two and only two files: a 16×16 pixel
/favicon.ico and a 152×152 pixel
/images/apple-touch-icon.png. You’d then reference the latter with a tag within your HTML. The
.ico version can include multiple resolutions inside it—the more, the better.
As developers I think we should push back a little and to make platform designers accept this approach and to gracefully work if this is all that’s available.