Pickman's Gift

Pickman's Gift is a quest in Fallout 4.

Quick walkthrough
You are given a key by talking to or looting Pickman and told to come back and look at his painting "Picnic For Stanley".

Detailed walkthrough
After killing all the raiders in Pickman Gallery you can speak with Pickman. You can accept the reward he tries to offer you or threaten and kill him and loot his body for the key. This begins the quest.

He tells you to take a closer look at his painting "Picnic For Stanley". After exiting the house, make your way back and re-enter through the front door. On this ground floor in the Northwest corner is a painting of a man with his eyes removed. Activate it to reveal Pickman's safe which is openable with the key obtained from Pickman.