A brief Wikipedia entry about Christy is here, a longer illustrated link is here and a Society of Illustrators tribute to him is here.
Part of his training was under William Merritt Chase, a grounding that must have enhanced his versatility, the facility that gained him success in the variety of undertakings noted above.
This seems to be a scan from a book published soon after the war in Cuba ended.
A wartime scene, but I'm not sure whether it was for a story or another purpose. Christy was highly skilled using water media.
A story illustration that looks like it was done using pen and brush.
She was the wife of the U.S. President, Calvin Coolidge.
Did I mention that he liked to paint saucy nudes?
The model standing at the left of the easel is draped a little, but the image on the canvas is draped not at all.
This huge painting is in the United States' Capitol Building.