When you migrate to Storefront 3.0, you probably will see that the customized delivery Group Icons are gone. There’s an Powershell command that brings those icons back, just run it on the Storefront Server:
& ‘C:\Program Files\Citrix\Receiver StoreFront\Scripts\ImportModules.ps1’
Disable-DSStoreSubstituteDesktopImage -SiteId 1 -VirtualPath /Citrix/Store
Note that you might have to Change the paths according to your Installation.