- In Chrome, right-click the image above. Choose “Copy Image”,
- In Finder, select /Applications/Google Chrome.app. Press Command-I.
- In the resulting Info pane click the old Chrome icon in the upper left corner. Press Command-V. (This is one of my favorite old Mac OS tricks. You can do this to any app/file, with any copied image.)
- Quit Chrome and restart.
If you’d like to use on Windows, please share steps in the comments. I can’t remember if there’s a quick way to use an image as an icon in Windows (aside from using tools to convert .png to .ico, which isn’t what I call quick.)