Tamara de Lempicka - In The Middle Of Summer
Georgia O'Keeffe - Pink Tulip
Violet Oakley - Quita Woodward
Séraphine de Senlis - Bunches of Grapes
There are two separate objects - one for female portraits, one for the floral paintings - with seven swatches each. You can see how swatches correspond to the paintings in the images below (click to enlarge). Some paintings have less frame options, that's because I felt certain frame colors just don't go well with the particular painting.
In game you can find this recolor with other paintings. It costs 1000 simoleons.