>>518879510
>She's singing about some girl Ophelia from a painting or some book

It is from Shakepeare's play Hamlet. Ophelia was betrothed to Hamlet until in Hamlet kills her father, Polonius, by accident as he mistook him for his step-father, Claudius, who was his uncle who married his brother's wife after he mysteriously died.

Hamlet basically thought that his mother marrying his father's brother was bullshit as he accused his uncle of having murdered his father, so he was trying to murder his uncle to take revenge, but instead he accidentally kills his future father-in-law instead of his step-father.

Ophelia is distraught over her future husband having killed her father and Hamlet doesn't help because he had implied the marriage was off.

Her death consisted of her sitting on a branch above a river and then falling in. The priest thinks she killed herself but her body doesn't even look damaged at all.

The paintings are because it was common to paint this scene of a body looking "incapable of its own death" as it implies a kind of melancholy where one isn't even suicidal but one might just accidentally sit on a branch over a river and fall in and do nothing to save oneself.