If you had bought this picture for $2 later to find out it's worth $5,000,000, would you feel an obligation to share some of the proceeds with the shop from which it was purchased?
If I had a good relationship with the store, or if it's a well-kept store that's a substantial boon to the community, sure. But otherwise it's like trading stocks - the seller was betting that the value is low and will continue to be low. Would you give money to the trader who sold you a stock that later dramatically rose in value?
