1- Michelangelo's - "The Hand of God" but more specifically, you are showing the part known as "The Creation of Adam".
2- Vincent van Gogh - "The Starry Night"
3- Leonardo da Vinci - "Mona Lisa"
4- Cassius Marcellus Coolidge - "A Friend in Need"
5- Franz Xavier Winterhalter - "The Empress Eugenie Holding Louis Napoleon, the Prince Imperial on her Knees"
6- Diego Rodriguez de Silva Velazquez - "The Needlewoman"