dedikleri: what they called
olsa gerek: must be
dedirten: what makes (somebody) to say
Kara sevda dedikleri bu olsa gerek: What they called 'black love' must be this
İnsanlık ölmemiş dedirten fotoğrafları: His/Her/Its/Their* photographs that make (people) to say humanity isn't dead.
* It's not clear if it's The or His/Her/Its/Their