Open your Page's admin panel
From the Manage menu, select Edit Page
Select Apps from the left sidebar
Click Edit Settings under the name of the app whose icon you want to change
Click Change next to Custom Tab Image
On the next screen, click Change next to the existing image
Follow the instructions that appear for uploading a new image or deleting the existing image
For some apps, the developer has chosen not to make the app's icon customizable and you won't be able to change it.
Neriman Publishing and Media
http://www.NerimanPublishing.com