If you’re dealing with a lot of third party applications in OS X, you’re going to end up looking at some butt-ugly icons from time to time. However, it is fairly simple to simply swap out the default icon file with another.
1) Navigate to said butt-ugly application in the Finder.
2) Control-Click on the application, then click “Show Package Contents” in the contextual menu.
3) Navigate from there to Contents>Resources.
4) In this folder you will find the ugly icon (Usually with a name like PS_App_Icon.icns). Archive the image if you might want it back.
5) Remove the ugly icon, and replace it with another icon file of your choice.