Oldest Known Images of Apostles Found in Rome

I have just noticed this story appearing on newspaper websites. Frescoes discovered in the catacombs under Rome date back to the 4th century AD and in some cases are the earliest known images of the apostle depicted, for example St Paul. This link here has the best photographs I have found. It's all so new that we can't reproduce them here. What is interesting to me looking at these is how they all correspond to the traditional characteristics of each apostle - for example the baldness of St Paul. There is also a depiction of Christ as the Good Shepherd, which is in accord with other images in the catacombs.