What format can I put for the icon?
I want to change the boring icon of the folder icon. But I tried to put the Jpeg format icon and I failed! What format can I put for the icon?
MacBook Pro with Retina display, OS X Mountain Lion (10.8.3), Icon
Are you trying to change one of the system level folder icons (so that every folder of that type uses your new icon) or specific folder icons for folders you have created?
The first requires special techniques that modify system level resources & is not recommended unless you know exactly what you are doing.
The second should work just like in the article.