image generation API batch requests: what the n parameter actually saves

Every image model takes an n parameter and multiplies cost linearly.

Model	Per image	n range	4 images
Flux	5 credits	1–4	20 credits
Nano Banana	4 credits	1–4	16 credits
Ideogram	6 credits	1–4	24 credits

There is no batch discount. Four images in one call costs exactly what four separate calls cost.

What you actually buy

Concurrency slots. Ceilings are per API key:

Tier	Requests per minute	Concurrent jobs
Free	5	1
Pro	60	5

On the free tier you get one in-flight job. Four images in one call is one job; four separate calls is four, and three of them come back with 429 CONCURRENCY_LIMIT_EXCEEDED.

Batching also costs you fewer requests against the per-minute limit — one instead of four.

Above the cap

n over the maximum fails validation with 400 INVALID_PARAM. Nothing is submitted and no credits are touched.

Models covered on this page

• FLUX Pro
• Nano Banana
• Ideogram v3