Shown above is a painting in the church of the boys' accomplishment. A label in the church says it is by Antonio Zanchi (1631-1722) and dates the painting at 1690, but the Italian Wikipedia says the tower seen in the background of the painting was constructed between 1703 and 1714. At any rate, the church shown in the painting is now only the central nave, two side aisles having been added at some later date.
The church also has a painting of martyrdom of Bishop Albanus and one of the others. The bishop is identified by his cope and by the mitre and crozier that have been rudely cast to the floor of the scaffold. In their vita, Albanus was killed in Mainz but Ursus had already been martyred when they passed through Aosta. Thus, the beheaded man below the scaffold should be Dominicus. The execution was ordered not by a Roman official as shown here but by Arian heretics (Acta Sanctorum, June vol. 4, 87-88).
Apparently there is also a legend about a shipwreck averted through the intercession of the three martyrs, for another painting in the church is SS. Lawrence Justinian, Albanus, Ursus, and Dominicus Save the Sailors (G. Brusaferro and A. Marini, 1710):
The Catholic Encyclopedia has an article on St. Lawrence Justinian, the first Patriarch of Venice. Perhaps the shipwreck legend was influenced by stories of St. Nicholas and St. Mark helping sailors in distress. The two figures in front are Bishop Albanus and Lawrence Justinian, the former dressed as a bishop with mitre and crozier, the latter as a "patriarch." The man with the tonsure behind them should be St. Dominicus, referred to as a "hermit" by the church plaque and thus more likely to have a full tonsure than the deacon Ursus.
View full-resolution copies of the painting of the three boys, the painting of the martyrdom, and the painting of the storm.
Read more about images of St. Ursus of Aosta.