What hinders the smooth transition is attachment, grief, crying etc. Deep affection, love, wish and prayer to have a safe journey are helpful. Of course all this is about the inner state. Putting a picture is of course not of much consequence for the departed though may be a way of remembrance and even deriving some support for those left behind. Plenty of people do this and most Indian homes traditionally kept the picture of their departed parents in their Pooja room or on one of the walls in their house. I don’t see why it should be a problem.
Affectionately,
Alok Da