Manifest - Icons

One or more icons that represent the extension, app, or theme. You should always provide a 128x128 icon; it's used during installation and by the Chrome Web Store. Extensions should also provide a 48x48 icon, which is used in the extensions management page (chrome://extensions). You can also specify a 16x16 icon to be used as the favicon for an extension's pages. The 16x16 icon is also displayed in the experimental extension infobar feature.

Icons should generally be in PNG format, because PNG has the best support for transparency. They can, however, be in any format supported by WebKit, including BMP, GIF, ICO, and JPEG. Here's an example of specifying the icons:

"icons": { "16": "icon16.png",
           "48": "icon48.png",
          "128": "icon128.png" },

Important: Use only the documented icon sizes.

You might notice that Chrome sometimes resizes these icons down to smaller sizes. For example, the install dialog might shrink the 128-pixel icon down to 69 pixels.

However, the details of Chrome's UI may change between versions, and these changes assume that developers are using the documented sizes. If you use other sizes, your icon may look bad in future versions of the browser.

If you upload your extension, app, or theme using the Chrome Developer Dashboard, you'll need to upload additional images, including at least one screenshot of your extension. For more information, see the Chrome Web Store developer documentation.