Reynolds sought to elevate British painting, including portraiture, to the lofty realms of classical expression. After traveling to Rome, Florence, Bologna, and Venice, Reynolds became the first president of the Royal Academy, which had been founded in 1768. Through his teaching at the Academy and the publication of his annual lectures, the Discourses, he urged the adoption of grand classical values and the study of Greek and Roman sculpture and Renaissance painting.
In Lady Delmé, Reynolds created an image of idealized, majestic feminine grace that has many precedents in Renaissance art. The pyramidal composition of the sitters, Lady Delmé's encircling arms and quiet manner, and the regal folds of the deep-rose drapery across her knees are reminiscent of Madonna and Child compositions by Raphael.
The rich, warm colors of the informal landscape and the beautifully controlled movement of light into the deep reaches of the background owe much to Titian. Finally, Reynolds' sensitive use of everyday, intimate details prevents the portrait from becoming remote and unapproachable. The tenderness with which Lady Delmé holds her two children, the nuances of personality in the three faces, the realistic costumes of the young sitters, and the attentive posture of the Skye terrier give the painting a worldly, familiar context.
More information on this painting can be found in the Gallery publication British Paintings of the Sixteenth through Nineteenth Centuries, which is available as a free PDF https://www.nga.gov/content/dam/ngaweb/research/publications/pdfs/british-paintings-16th-19th-centuries.pdf