The Portrait of Kan'nackle

Legends tell of a haunted portrait that brought a city to ruin. The gnomish city of Kan'nackle is lost, but it is believed to still stand, completely intact but abandoned. Legend has it that one of the noble houses commissioned a portrait to honor their matriarch at the end of her life. On her deathbed, in her last moments, her grandchildren (believing her already dead) cheered her death and their impending inheritance. This unleashed a rage that carried her into undeath, bound to her portrait that hung above her bed.
The portrait took on a hideous visage, and over the following days, all the other portraits in the manor were similarly corrupted. Within a month, the entire family had perished. Each died mysteriously near a corrupted portrait. But the matriarch's curse did not end there, and lost in her rage, she continued to kill indiscriminately. The corruption of portraits and other paintings spread throughout the city. Many died from the horrible figures they contained, and eventually the rest fled the city to escape the curse.
A cleric eventually returned to consecrate and burn the portraits, only to find that they had all reverted to their original appearance. Except for the portrait of the Matriarch, which was nowhere to be seen. The cleric continued his mission and burned all the paintings he could find. And at the end of his work, he said a prayer for the unfortunate soul who had claimed her portrait. He feared that if it were taken to another city, it would wreak the same havoc as it had in Kan'nackle.