In response to a query, here are some websites where you can search for religious art online. Most of them make available historical images for any use. Some have restricted use - such as online viewing but not download - hence you can share the link or provide a device for people to view the art. Feel free to notify me of additional sites.
Vanderbilt University Library
Web Gallery of Art
Methodist Art Collection (UK)
Metropolitan Museum of Art - Free Images - go to page and select "Open Access Artworks"
National Gallery of Art
Rijks Museum
Smithsonian Open Access
Art Institute of Chicago
I'd also recommend ArtWay as a great portal to explore art and religion.
You can also search here for photos that people have taken of public art pieces.
https://www.pexels.com/
https://unsplash.com/
These are all listed on my page Multimedia and Design Resources - listed right.
Image: ALTDORFER, Albrecht, Christ on the Cross between Mary and St John, c. 1512
Limewood, 102 x 116 cm
Source: Web Gallery of Art
