Breezing Up (A Fair Wind), Winslow Homer
Link is to zoomable version on Google Art Project; there is a downloadable version on Wikipedia, along with a page devoted to the painting. The original is in the National Gallery of Art, DC, which also has downloadable files.
As much as Homer is noted for his watercolors — and rightfully so — I really admire his oil paintings. The brushwork and surface texture in this work are an absolute delight.
Link: Breezing Up (A Fair Wind), Google Art Project