Great song. The person who loves knows that the person who he loves is totally apathetic to the feelings being felt. When he says " I'm in the middle of your picture" he is expressing that even though he is the focus of the picture(middle) the loved one still ignores him and his feelings, but that's O. K. Because that's " ... all I need". In the end he laments that this kind of love is painful and questions it's validity because it's wrong that his love is not being returned, but at the same time he loves this person so much that its a moot point to even question it- " it's all wrong/it's all right".