Are you getting near the end of your application design but need an icon? Have an icon designed in Photoshop but aren’t sure how to turn it into an icns file? Or maybe you’re like me and got a new icon pack for your mac but it was missing some icons so you decided to fill in the blanks yourself. Either way, to create an icon for OS X it must be an icns file. To create it you must have an application called Icon Composer. To get the program you have to download the Xcode developer tools from developer.apple.com (you can create an account for free).
Now that you have that, let’s move to Photoshop (or whatever other program you created your icon in)
In Photoshop make sure that your icon is 512×512 and fully transparent.
Now we’re going to go ahead and save that file as a png file.
Now let’s open up icon composer and create out icon! The program is located at /Developer/Applications/Utilities/
Once you open it up you’re going to see a whole bunch of views for different sized images. Simple drag your png file into the 512×512 view, then drag it to all the smaller views aswell.
Now just save the file and you have an icns file! To replace an application icon simply right click on an application > show package contents > Contents/Resources > look for an icns file containing the application’s icon (name your icns file accordingly) then drag and drop your icns file in replacing the original icns file. Now just log out and back in and your icon will be changed!
That’s what my new transmit mounted server icon looks like on my desktop with my other disks (perfectly matching my theme!).
Hope you enjoyed this tutorial, please share the tutorial or comment to let others know just how awesome it is!