FLUX 3 Image 4K at $0.607 vs Nano Banana 2 4K on Sume: 50 images

Black Forest Labs' pricing docs (read 2026-10-03) list FLUX 3 Image at four sizes: $0.041 at 768sq, $0.048 at 1k (about 1 megapixel), $0.100 at 2k (about 4 megapixels) and $0.607 at 4k (about 16 megapixels). The 4k tier is more than six times the 2k tier.

FLUX 3 is not in Sume's rate tables, so this post compares the 4K price against the nearest 4K option Sume lists: Nano Banana 2, at $0.20 per 4K image after Sume's 1.25 multiplier (provider list $0.16).

A 50-image hero set

Say you need 50 finished 4K hero images, with no allowance for rejects. FLUX 3 Image at 4k is 50 times $0.607, which is $30.35. Nano Banana 2 at 4K on Sume is 50 times $0.20, which is $10.00. Google's own Gemini API pricing lists Nano Banana 2 at 4K for $0.151 per image, so direct from Google it would be $7.55.

The 2k alternative

If a 4-megapixel image is enough, FLUX 3 at 2k is $0.100, so 50 images is $5.00, cheaper than Sume's Nano Banana 2 at 4K. Whether 2k suffices depends on your output: a 2k image covers a full-width web banner but not a large print. Do not pick a 4K tier before checking where the image will be shown.

Prices are only half of the decision. A model that follows your brief on the first take is cheaper than one that needs three, so test a few prompts on each before buying 50.

Quick calculator

Paste your own counts and rates into this snippet.

options = {
    'flux 3 4k (BFL)': 0.607,
    'flux 3 2k (BFL)': 0.100,
    'nano banana 2 4K (Google)': 0.151,
    'nano banana 2 4K (Sume)': 0.20,
}
count = 50
for name, per_image in options.items():
    print(f'{name}: ${per_image * count:.2f}')