This page explains how to start and complete the A Shady Customer side quest.
How to Start the Quest
Talk to Hoz at the East Akkala Stable, which is near Katosa Aug Shrine, to start the quest.
How to Complete the Quest
Hoz wants to see a picture of Kilton. You can find Kilton in the eye of Skull Lake, which is northwest of the East Akkala Stable at night (or in various towns at night if you have found him in Skull Lake already). Take a picture of Kilton, then go back to the stable and show Hoz the picture of Kilton to get a Silver Rupee.