You need to deserialize direcly to a list of your class:
Dim json As String = "[ {""picture"":""URL_PIC_1"", ""link"":""URL_LINK_1""}, {""picture"":""URL_PIC_1"", ""link"":""URL_LINK_1""} ]"
Dim items As List(Of BonusItems) = JsonConvert.DeserializeObject(Of List(Of BonusItems))(json)
The deserialize should take care of the rest, so long as things match up properly.