Oh, no problem--it was fun to research, actually. Reverse image search makes it a lot easier than it would have been a few years ago.

@lilymhudson, As an art history nerd, I could not let these works go unattributed, either. After a little research, I came up with the following list (sorry, I couldn't find dates for all of them):

1. Titian or Giorgione: Pastoral Concert, c. 1509

2. Gabriel Metsu: The Letter Writer Surprised, c. 1662

3. Giorgione: Youth with a Guitar and Two Girls on a River Bank

4. Abraham Bloemart: Pastoral Scene with a Herdsman's Family in Front of a Landscape

5. Eugène de Blaas: The Serenade

6. Gustave Dutailly: A Young Man Serenading A Woman Who Reclines Asleep Upon A Bench

7. François Boucher: Shepherd Piping to a Shepherdess, 1744

8. Federico Andreotti: The Persistent Suitor

9. Jean-Louis Forain: Behind the Scenes, c. 1880

10. Édouard Manet: In the Conservatory, 1879

11. Jean-Louis Forain: Tribunal Scene, 1906

12. Édouard Manet: The Balcony, 1868

13. Édouard Manet: At Father Lathuille, 1879

In case someone wanted to know the list of artists and titles, I came up with the following:

1. Titian or Giorgione: Pastoral Concert, c. 1509

2. Gabriel Metsu: The Letter Writer Surprised, c. 1662

3. Giorgione: Youth with a Guitar and Two Girls on a River Bank

4. Abraham Bloemart: Pastoral Scene with a Herdsman's Family in Front of a Landscape

5. Eugène de Blaas: The Serenade

6. Gustave Dutailly: A Young Man Serenading A Woman Who Reclines Asleep Upon A Bench

7. François Boucher: Shepherd Piping to a Shepherdess, 1744

8. Federico Andreotti: The Persistent Suitor

9. Jean-Louis Forain: Behind the Scenes, c. 1880

10. Édouard Manet: In the Conservatory, 1879

11. Jean-Louis Forain: Tribunal Scene, 1906

12. Édouard Manet: The Balcony, 1868

13. Édouard Manet: At Father Lathuille, 1879