There are a number of reasons to want a Mac App icon. Maybe you want to create a how-to document for a class. Maybe you want to customize a folder icon on your desktop. Maybe you want to create a header for a blog (like the one above). Who knows why you’d want the icons. There are a couple ways to do what you’re wanting to do though. I’m assuming you have OSX 10.5 or better.
To change a Mac folder (or document icon)
1) In the Finder, click ONCE on the document or folder icon you want to copy.
2) Press cmd-i (for “get info”). An informational window should appear.
3) In this new informational window click ONCE on the icon you want to copy.
3) Press cmd-c (to “copy” the image to your clipboard).
4) Close the informational window and click ONCE on the document or folder you want to change.
5) Press cmd-i. The familiar informational window should appear.
6) Click ONCE on the icon you want to change.
7) Press cmd-v (to “paste” the image from your clipboard).
The nice thing about this approach is if the SOURCE image has transparent spots (also known as an alpha channel) in it… it will carry through to the TARGET file/folder icon. If you already have an image on your clipboard you can simply follow the second half of the instructions above and voila!
Copying App Icons Into Photoshop Layers
There are times when you may want to create a picture with a clean icon in it. Copying and pasting the “get info” icon doesn’t quite cut it for Photoshop. Yes, the icon gets copied. Yes, you can paste it. But the alpha channel gets lost and your icon comes through with a white background on the same layer as the icon you wanted. That may not quite be what we intended. Not to worry though. There is a better way.
FYI: I’m using Photoshop CS5 and think this applies to older and newer versions but reserve the right to be wrong This is a little more involved of a process. The steps below are pretty straight forward. But, the video may be easier to follow for some. [Video added after the original posting] This procedure is for copying an APPLICATION ICON for use in an image editing app.
1) In the FINDER ctrl-click on the icon you want to copy. A contextual menu will pop up. Select “Show Package Contents”
2) A new folder will open and depending on the app you’ll see a “Contents” folder and maybe some others.
3) Open the “Contents” folder.
4) Inside that you’ll see a few more files. One of them will be a .icns file. Usually the one you’ll want is your App name + the icns suffix. For example: iDVD.icns
5) Open the .icns file with something like Preview.
6) There may be multiple “pages” to the icns file. Select the first page’s thumbnail.
7) Select “Export” from the FILE menu.
8) The format you want to export as is PNG and you definitely want the Alpha channel checked. Save it where you want and named as you like.
9) Now, simply open that file in your image editor.
You now have a super high resolution app icon with exceptionally crisp edges. Yes, you could have achieved something acceptably close with some of the image editing tools. But, this way you have edges every bit as good as the app author is using for their own purposes.