FLUX.3 4K at $0.607 vs Nano Banana 2.1 4K at $0.20 on Sume: 11 heroes

Eleven 4K hero images cost $6.677 at the FLUX.3 Image list price of $0.607 per 4K image on Black Forest Labs' pricing page, and $2.20 with Nano Banana 2.1 at 4K on Sume, which is $0.20 per image. Sume does not list FLUX.3 as of 2026-10-09, so the first number is a vendor price you cannot buy through Sume, and the second is a Sume price.

The comparison is about budget, not quality. The two models make different pictures, and a 4K price is only worth comparing when a 4K image is what you need.

What each side lists

Black Forest Labs prices FLUX.3 Image per image by resolution: 768sq (768 x 768) at $0.041, 1k (about 1 megapixel) at $0.048, 2k (about 4 megapixels) at $0.100 and 4k (about 16 megapixels) at $0.607. Its page says the submission response includes the cost of each request.

If you only need 1K

The ratio changes with size. At 1k, FLUX.3 is $0.048 on the vendor page, against $0.10 for Nano Banana 2.1 at 1K on Sume. Eleven images would be $0.528 against $1.10. So FLUX.3 is the more expensive model at 4K and the cheaper one at 1K by list price, and the break-even is a size question you answer per project.

Sume lists FLUX.2 Pro at $0.0375 per image, which is below the 1k FLUX.3 list price. If you need the FLUX family on Sume today, that is the one to price.

How a Sume image job is billed

Image generation on Sume is all-or-nothing. A completed generation is billed in full and a failed one is not billed. The endpoint pricing lines are what your wallet pays and already include the Sume margin, so the cost for n images is the line price times n.

Reservations still apply: at submit, Sume holds the estimated amount, and a 402 comes back if the balance cannot cover it. Eleven 4K Nano Banana jobs hold $2.20 at once in the worst case.

A note on what 4K is for

Most delivery surfaces do not need 16 megapixels. A hero used in a web page at 2560 pixels wide is well served by 2K, which is $0.100 for FLUX.3 and $0.15 for Nano Banana 2.1 on Sume. The 4K figures matter for print, large displays or crops. Eleven images at 2K is $1.10 on the BFL list and $1.65 on Sume. Choose the size from the delivery spec first, then price the models that can produce it. Black Forest Labs also states that its submission response includes the cost of each request, which is a good way to check a vendor bill.