[VanillaEps]

I've changed a number of icons on my MBP. Recently, my Safari icon has reverted back to its original icon. But, when I try to change it back using Copy and Paste, nothing happens. I tried doing the same with another application and it seems to be working. Why is Safari being stubborn with its icon. I've had the altered icon for a few weeks now.

What gives?

[Caesar2099]

In short:
All applications in Mac OS X have a file in its Package Contents titled "App.icns"
or "iChat.icns" for iChat, etc.
This file is where the icon is originally drawn from, not from File>Get Info

Applications like Candybar will replace the original .icns file rather then just paste a new icon in the Get Info window. I would suggest using Candybar instead, to avoid further issues.