Seed&Image Size

Seed * Noise = Seed noise

Seed is numeric by default.

The CPU and GPU generate random numbers. So remember to keep it constant.

It's just a number.

"PROMPT" * SEED = Various Pictures

SEED is just a number 
SEED * Image Size(SEED size) = SEED NOISE

Using the same Seed will generate similarly shaped images.
But!
1. Seed noise = Seed * Image size
2. Prompt > Need a clear topic (for strong cohesion)
The above two conditions are necessary.