Learn Finnish: Valokuvaaja seisoo minun edessäni, ja minä hymyilen paljon. - The photographer stands in front of me, and I smile a lot.

This is the core of inflecting postpositions! When a postposition is used with a personal pronoun (like minun), it takes a possessive suffix that matches the pronoun. Since minun is the first-person singular ("my" or "me"), we attach the matching suffix -ni to the postposition edessä.

Are the pronouns minun and minä strictly necessary in this sentence?

No, you can drop both of them! The suffix -ni on edessäni already tells us it means "in front of me", and the -n ending on hymyilen already means "I smile". Including the pronouns just adds a bit of emphasis or sounds more poetic.

The word edessä means "in front of", but why does it have the -ssä ending?

Many Finnish postpositions are based on location cases. The -ssä is the inessive ("in") ending. So, edessä literally translates to "in the front". Adding the possessive suffix makes it edessäni, which you can think of literally as "in my front"!

How do you break down the word valokuvaaja?

This is a great example of Finnish word building. Valo means "light" and kuva means "picture" (together making valokuva, or photograph). The -ja at the end works like the English "-er", turning the word into the person doing the action: a photographer.