Icons and manifest.json

Question

What are the recommendations on how to deal with icons in manifest.json?

I found this webpack plugin that generates icons. It generated 37 icons and the corresponding HTML tags.

<meta name="mobile-web-app-capable" content="yes">
<meta name="theme-color" content="#fff">
<meta name="application-name" content="graff">
<link rel="apple-touch-icon" sizes="57x57" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-icon-57x57.png">
<link rel="apple-touch-icon" sizes="60x60" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-icon-60x60.png">
<link rel="apple-touch-icon" sizes="72x72" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-icon-72x72.png">
<link rel="apple-touch-icon" sizes="76x76" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-icon-76x76.png">
<link rel="apple-touch-icon" sizes="114x114" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-icon-114x114.png">
<link rel="apple-touch-icon" sizes="120x120" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-icon-120x120.png">
<link rel="apple-touch-icon" sizes="144x144" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-icon-144x144.png">
<link rel="apple-touch-icon" sizes="152x152" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-icon-152x152.png">
<link rel="apple-touch-icon" sizes="180x180" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-icon-180x180.png">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
<meta name="apple-mobile-web-app-title" content="@dasnoo/graffity-inferno">
<link rel="apple-touch-startup-image" media="(device-width: 320px) and (device-height: 480px) and (-webkit-device-pixel-ratio: 1)" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-startup-image-320x460.png">
<link rel="apple-touch-startup-image" media="(device-width: 320px) and (device-height: 480px) and (-webkit-device-pixel-ratio: 2)" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-startup-image-640x920.png">
<link rel="apple-touch-startup-image" media="(device-width: 320px) and (device-height: 568px) and (-webkit-device-pixel-ratio: 2)" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-startup-image-640x1096.png">
<link rel="apple-touch-startup-image" media="(device-width: 375px) and (device-height: 667px) and (-webkit-device-pixel-ratio: 2)" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-startup-image-750x1294.png">
<link rel="apple-touch-startup-image" media="(device-width: 414px) and (device-height: 736px) and (orientation: landscape) and (-webkit-device-pixel-ratio: 3)" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-startup-image-1182x2208.png">
<link rel="apple-touch-startup-image" media="(device-width: 414px) and (device-height: 736px) and (orientation: portrait) and (-webkit-device-pixel-ratio: 3)" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-startup-image-1242x2148.png">
<link rel="apple-touch-startup-image" media="(device-width: 768px) and (device-height: 1024px) and (orientation: landscape) and (-webkit-device-pixel-ratio: 1)" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-startup-image-748x1024.png">
<link rel="apple-touch-startup-image" media="(device-width: 768px) and (device-height: 1024px) and (orientation: portrait) and (-webkit-device-pixel-ratio: 1)" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-startup-image-768x1004.png">
<link rel="apple-touch-startup-image" media="(device-width: 768px) and (device-height: 1024px) and (orientation: landscape) and (-webkit-device-pixel-ratio: 2)" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-startup-image-1496x2048.png">
<link rel="apple-touch-startup-image" media="(device-width: 768px) and (device-height: 1024px) and (orientation: portrait) and (-webkit-device-pixel-ratio: 2)" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/apple-touch-startup-image-1536x2008.png">
<link rel="icon" type="image/png" sizes="32x32" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="16x16" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/favicon-16x16.png">
<link rel="shortcut icon" href="icons-ce3ab881bd31f1efc59c9c227d8f6b7f/favicon.ico">

For optimal results, should I put the icons in my manifest.json file and HTML meta tags? What would having 37 icons achieve that I wouldn't have with say 10 icons (I assume it's more mobile support, but if 3 icons handle 95% of browsers, it effectively achieve nothing)? What are the recommended ones?

This is for a service worker.

Answer 1

You're correct, each of those icons is for a different device and often a different version of said device. However, you don't really need 37. To get 37, they generate pixel perfect icons for devices that have much less than 1% market share. You can just provide the nearest match for them and almost no one will even notice. I tend to put browser related icons in the HTML meta tags and app related icons in the manifest.

Here is a good post about all of this.

Answer 2

At a baseline, you should be following the structure of the manifest below. More details can be found on this link. Though if you run Lighthouse against your PWA, it will ask for another icon sized at 512px.

{
    "name": "HackerWeb",
    "short_name": "HackerWeb",
    "start_url": ".",
    "display": "standalone",
    "background_color": "#fff",
    "description": "A simply readable Hacker News app.",
    "icons": [
        {
            "src": "images/touch/homescreen48.png",
            "sizes": "48x48",
            "type": "image/png"
        },
        {
            "src": "images/touch/homescreen72.png",
            "sizes": "72x72",
            "type": "image/png"
        },
        {
            "src": "images/touch/homescreen96.png",
            "sizes": "96x96",
            "type": "image/png"
        },
        {
            "src": "images/touch/homescreen144.png",
            "sizes": "144x144",
            "type": "image/png"
        },
        {
            "src": "images/touch/homescreen168.png",
            "sizes": "168x168",
            "type": "image/png"
        },
        {
            "src": "images/touch/homescreen192.png",
            "sizes": "192x192",
            "type": "image/png"
        }
    ],
    "related_applications": [
        {
            "platform": "web"
        },
        {
            "platform": "play",
            "url": "https://play.google.com/store/apps/details?id=cheeaun.hackerweb"
        }
    ]
}