How Do I Change Artwork

I have been trying to change the default images, using the videoplayer template, but I can't seem to change them. The overhang logo and the background still stays as the default TED logo and background.

I am new to ROKU, so I don't know if I changed the right things. I modified the appMain to:

'

********************************************************************
'** Video Player Example Application - Main
'** November 2009
'** Copyright (c) 2009 Roku Inc. All Rights Reserved.
'********************************************************************

Sub Main()

'initialize theme attributes like titles, logos and overhang color
initTheme()

'prepare the screen for display and get ready to begin
screen=preShowHomeScreen("", "")
if screen=invalid then
print "unexpected error in preShowHomeScreen"
return
end if

'set to go, time to get started
showHomeScreen(screen)

End Sub


'*************************************************************
'** Set the configurable theme attributes for the application
'**
'** Configure the custom overhang and Logo attributes
'** Theme attributes affect the branding of the application
'** and are artwork, colors and offsets specific to the app
'*************************************************************

Sub initTheme()

app = CreateObject("roAppManager")
theme = CreateObject("roAssociativeArray")

theme.OverhangOffsetSD_X = "72"
theme.OverhangOffsetSD_Y = "31"
theme.OverhangSliceSD = "pkg:/images/roku-background-sd.jpg"
theme.OverhangLogoSD = "pkg:/images/roku-channel-sd.png"

theme.OverhangOffsetHD_X = "125"
theme.OverhangOffsetHD_Y = "35"
theme.OverhangSliceHD = "pkg:/images/roku-background-hd.jpg"
theme.OverhangLogoHD = "pkg:/images/roku-channel-hd.png"

app.SetTheme(theme)

End Sub

Is there something I am missing out or doing wrong?

Thanks!