Art and the Bible - can view biblical images by artist's name. Images are linked to the biblical text.
Art and Religion - National Gallery Research Theme - focuses on Christian art
Art in the Christian Tradition - " The Art in the Christian Tradition (ACT) database is a freely available, regularly updated visual image internet resource. Designed for scholars, students, pastors, and religious educators, all of the images may be used for educational and/or religious non-profit purposes. Images are added regularly. There are currently 4469 images in the collection."
Basel Mission Archives - "digitized visual and cartographic material.... some 30,000 images, 6700 maps, sketches and plans"
Pitts Theology Library Digital Image Archive - "The Digital Image Archive presents more than 48,000 images of biblical illustrations, portraits of religious leaders, printers' devices, engravings of church buildings, and other theological topics. They are available for teaching, research, and other non-commercial purposes.". Many of the images are from the Kessler Reformation Collection (emphasis on Lutheran material)