Image vs Bitmap

[Cavecat]

Hello!

I wanted to know what is best to use for a picturebox.image - a bitmap variable or an Image variable. I have embedded resources (.png, .ico, and .jpg). I access them through calling a function from a class.

Public Class Items

    '-----------------------------------------------------------------------------------------------------------------------------------------------------------
    'ITEM
    Public Function Get_Item(ByRef ItemName As String) as Bitmap 'or As Image

        Dim Item As Bitmap = New Bitmap(System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceStream("I_Res." + LTrim$(ItemName) + ".ico"))' can change the Item type to Image
        Return Item
        Item.Dispose()

    End Function
    '-----------------------------------------------------------------------------------------------------------------------------------------------------------

End Class

So what is best to do?

1) Declare an Image variable and get an image type from the resources (if it is "As Image")

Dim tmpImage As Image = (Items.Get_Item("Item1"))

or

2) Declare a Bitmap variable and get a bitmap from the resources? (if it is "As Bitmap")

Dim tmpImage As Bitmap=new bitmap(Items.Get_Item("Item1"))

3)-Is it best to declare a variable first as above and then put it in picturebox (PictureBox1.Image=tmpImage)
-Or I can just put it in the picturebox straight ahead? (PictureBox1.Image=new bitmap(Items.Get_Item("Item1"))

4)Do I need to call Dispose on the variables in the Function?

Thank you in advance!