OpenArtViewer uses National Gallery of Art Open Data API. The included SQLite database has stored info about the artworks including image links to the artworks on the NGA server.
From the GUI you can search type of art and by title, year, artist. To the left there's a scroll bar with the results as thumbnails. These can be clicked to get more information and a higher resolution version of the artwork in the big panel to the right. A high resolution image can then be downloaded. Made in Unity. Download this program (Windows)