My application\'s main icon consists of two parts in one image: a logo and a few letters below it. This works well for the launcher icon for the app, but when the icon appea
Might wanna check this, got everything you need for your app icons
http://developer.android.com/guide/practices/ui_guidelines/icon_design.html
update
I think by default it uses your launcher icon... Your best bet is to create a separate image... Designed for the action bar and using that. For that check: http://developer.android.com/guide/topics/ui/actionbar.html#ActionItems