The oldest and most famous frescoes are kept in the small church of St. Jerome at the Hum cemetery. These frescoes dating from the second half of the 12th century are a very rare example of Byzantine painting in these parts. Fragments of The Annunciation are preserved on the triumphal arch, on the southern wall was the cycle from the life of Christ where only a detail of The Visitation has been preserved, while on the northern wall the following details from the cycle of Christ's Passion remain: Last Supper, Juda's Kiss, Crucifixion, Deposition from the Cross and The Entombment. In the lower part of the northern wall is a preserved fragment presenting images of the martyrdom of St. Lawrence.
The painted walls have been inscribed with numerous Glagolitic graffiti, among them is the famous Hum graffito.