```mermaid
graph TD
A[User Input: Niche/Topic] --> B{Niche Researcher}
B --> |JSON: 5 niche-specific keywords| C{Slogan Generator}
C --> |JSON: 3 generated slogans| D{Image Generator}
D --> |6 JPEG images 1200x1800| E{Birthday Card Assembler}
E --> |6 complete birthday card images| F{Output Compiler}
F --> |Task summary, image URLs, HTML selector| G[Final Output]
```