Seville's most popular painter in the later 17th century was Bartolomé Esteban Murillo.
While Murillo is well known for works with religious themes, he also produced a number of genre paintings of figures from contemporary life engaged in ordinary pursuits. These pictures often possess a wistful charm; Two Women at a Window is a striking example. A standing woman attempts to hide a smile with her shawl as she peeks from behind a partially opened shutter, while a younger woman leans on the windowsill, gazing out at the viewer with amusement. The difference in their ages might indicate a chaperone and her charge, a familiar duo in upper-class Spanish households. Covering one's smile or laugh was considered good etiquette among the aristocracy.
The convincingly modeled, life-size figures, framed within an illusionistically painted window, derive from Dutch paintings that were meant to fool the eye.
More information on this painting can be found in the Gallery publication Spanish Paintings of the Fifteenth through Nineteenth Centuries, which is available as a free PDF https://www.nga.gov/content/dam/ngaweb/research/publications/pdfs/spanish-painting-15th-19th-centuries.pdf