MIDJOURNEY PROMPT WEIGHTS
Midjourney prompt weights consider two or more separate concepts within a prompt individually. This is done using the :: separator.
PROMPT WEIGHT VS IMAGE WEIGHT
Prompt weights are a way to shape your image generation by weighting the text in your prompts.
car:: paris:: summer
Image weights are a way to shape image generation when using an image(s) as part of your image prompt.
car paris summer --iw .75
Note: you can use both types of weighting together for an even more powerful effect.
USING MIDJOURNEY PROMPT WEIGHT
When writing weighted prompts, a number added to each part signifies its importance in the final image. The numbers tell MidJourney, “this part needs to be x-times more prominent than this part.”