Recommended size of icon for Google Chrome Extension
google-chrome-extension
Solution
Both are correct ! They are for different sections/features:
The former refers to the browser-action icon (displayed on the top-right corner of your browser-window, next to the address bar). It is only displayed if your extension registers a browser-action.
The latter refers to icons used throughout the extension and browser, as is explained quite clearly in the link you provide: (emphasis mine)
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.
BTW, that second link mentions `icon` as the property name, which was replaced in Manifest v2 by `default_icon`. ("Migration to Manifest v2" guide)
Problem
This page explain 19*19 and 38*38. http://developer.chrome.com/extensions/browserAction.html#icon But this page explain 16*16 and 48*48, 128*128. http://developer.chrome.com/extensions/manifest/icons.html Which is correct?