This picture is inspired by the story of the criminals who were also being crucified alongside of Jesus, which is quoted in Luke 23:26-43.  The verse from 39-43 reads: ‘one of the criminals who hung there hurled insults at him.  ‘Aren’t you the Christ? Save yourself and us!” But the other criminal rebuked him.  “Don’t you fear God,” he said, “since you are under the same sentence?  We are punished justly, for we are getting what our deeds deserve.  But this man has done nothing wrong.”  Then he said, “Jesus, remember me when you come into your kingdom.”  Jesus answered him “I tell you the truth, today you will be with me in paradise.”

The Living Bible study notes have a good teaching about this verse:

‘As this man was about to die, he turned to Christ for forgiveness, and Christ accepted him.  This shows that our works don’t save us – our faith in Christ does.  It is never too late to turn to God.  Even in his misery, Jesus had mercy on this criminal who decided to believe in him.  Our lives are much more useful and fulfilling if we turn to God early, but even those who repent at the very last moment will be with God in his Kingdom.’