In book 2, chapter 19, Molanus discusses how one should deal with artworks depicting matters from unestablished textual traditions. Foremost is that no false stories are depicted, but in the case of artworks based on uncertain stories, propriety and probability should prevail in the judgement and above all the common opinion of the whole Church.
The fourth example of such an iconographic tradition surrounded by uncertainty in the Scriptures is on which side of Christ the good thief has to be placed. However, this question is not answered in any of the Scriptures, according to Molanus the good thief has to be placed at Christ’s right hand.
“Which of the two thieves was crucified at the right hand of Christ is not shown in any of the Gospels; however, in the painting, the good or repentant thief is placed at his right hand.”
“Uter latronum a dextris Christi fuerit crucifixus, nullus Evangelistarum expressit, in picturis tamen banus sue poenitens latto dextero loco collocatur. “
Molanus 1996, 177.