How to Use Custom App Icons on a Mac
Changing an icon on a Mac is quite simple. It does not require any third party application as long as you replace the image with another .icns file. It’s not difficult if you just copy another app’s icon to your laptop or desktop.
But if you want to customize your own images, you’ll need some help. Apple requires these icons to be an .icns file, and as you might have guessed, most images are not saved in .icns format; you will need to convert them. We can do this with a free tool called Cloud Convert.
All you need to make it work is a square image and a tool like Cloud Convert to do the conversion. Once converted, you can follow the first part of this tutorial to replace any icon with the new, custom one.
Change app icon
1) Open Finder to access the app.
2) Applications open to see a list of all applications on your computer.
3) Right click on the app to open the context menu.
4) In the menu that opens, click Get Info.
5) Drag icon and drop on the icon in the application information window.
Convert images to .icns format
1) Go to https://cloudconvert.com/
2) Click Select File to start the process.
3) In the list that opens, select location folder.
4) Select picture that you need to convert.
5) Click Open to upload the file to CloudConvert.
6) Open the Convert to drop-down menu to select the size.
7) Select ICNS in the menu that opens.
8) Click Convert to download the icon in .icns format.