Painting

I've been staring at that painting
On the wall
But the lights are too dim
And the food is so good
The waitress is so pretty
With the narrow waist
And those wide hips
The music is too jolly
And the waitstaff wants me to leave
She brought me a check
And she smiled
And said,
"I'll be yourcashier when you're ready."
And I can't tell what that
Picture on the wall
Means.