Android Question Activity background image not loading

Sub spBkgColour_ItemClick (Position As Int, Value As Object)
    Dim strValue As String
    Dim bd As BitmapDrawable
    
    Log("spBkgColour Position is :" & Position & " and Value is " & Value)
    
    If Value = "Black" Then strValue = "1440x2560BLA.jpg"
    If Value = "Blue" Then strValue = "1440x2560BLU.jpg"
    If Value = "Green" Then strValue = "1440x2560GRE.jpg"
    If Value = "Orange" Then strValue = "1440x2560ORA.jpg"
    If Value = "Red" Then strValue = "1440x2560RXD.jpg"
    If Value = "Light Blue Plain" Then strValue = "1440x2560BUP.jpg"

    Main.BKG_IMAGE = strValue
    
    Log("Background file to load is " & strValue)
    
    If File.Exists(File.DirAssets, strValue) Then
        bd.Initialize(LoadBitmap(File.DirAssets,strValue))
        bd.Gravity = Gravity.FILL
        Activity.Background = bd
    Else
        Log("The file does not exist!!")
    End If
    
    
End Sub

Sub btnSave_Click
    'save all settings to file
    '1) background filename
    '2) Night Mode 1,2,3 1=On 2=Off 3=Auto
    '3) Night Mode ON time
    '4) Night Mode OFF time
    '5) Thumbnail Type 1=flower 2=cosmos 3=arabic
    '6) Reserved
    
    Dim us1, us2, us3, us4, us5, us6, lineData As String
    
    If Main.THUMBNAIL_IMAGE = "flower" Then Main.THUMBNAIL_IMAGE = "1"
    If Main.THUMBNAIL_IMAGE = "cosmos" Then Main.THUMBNAIL_IMAGE = "2"
    If Main.THUMBNAIL_IMAGE = "arabic" Then Main.THUMBNAIL_IMAGE = "3"
    
    us1 = Main.BKG_IMAGE
    us2 = Main.NIGHT_MODE
    us3 = Main.NIGHT_MODE_ON
    us4 = Main.NIGHT_MODE_OFF
    us5 = Main.THUMBNAIL_IMAGE
    us6 = Main.SETTINGS_RESERVE
    
    lineData = us1 & us2 & us3 & us4 & us5 & us6
    Log("userSettings Write data is " & lineData)
    
    'make file
    Dim writeLine As TextWriter
    
    writeLine.Initialize(File.OpenOutput(File.DirInternal,"userSettings.txt",False))
    
    writeLine.WriteLine(lineData)
    
    writeLine.Close
    
    Activity.Finish
    
End Sub