What operating system are you using ?
What avast version are you using (latest is 12.3.2280) ?
The tray icon is always going to be different as there are size constraints for icons in that location.
The desktop shortcut icon for avast hasn't changed for some considerable time, it is the same as yours on my winXP and win7 systems.
As far as I'm aware, the top Icon isn't actually an icon but a windows gadget for avast. Windows has actually depreciated the use of gadgets (vulnerabilities) as they are no longer supported, but if you had ones previously they would remain unless you remove them. I removed the avast Windows Gadget (on my win7 system) when windows stopped supporting them.