Harvest is related to Farm. Farm is related to Plot. Plot is related to Grave. Grave is the opposite of Serious. 
Photograph is related to Develop. Develop is related to Product. 
Harvest <--RelatedTo--> Farm <--RelatedTo--> Plot <--RelatedTo--> Grave <--Antonym--> Serious 
Photograph <--RelatedTo--> Develop <--RelatedTo--> Product 