FLUX.3 Image vs Seedream 5 Lite: price per image at 1K, 2K, 4K

Black Forest Labs lists FLUX.3 Image at $0.041 for 768 by 768, $0.048 for about 1 megapixel, $0.100 for about 4 megapixels and $0.607 for about 16 megapixels. Sume lists Seedream 5 Lite at a flat $0.04375 per image. That makes Seedream 5 Lite $0.00425 cheaper than FLUX.3 at 1k, 2.29 times cheaper at 2k and 13.9 times cheaper at 4k. Sume does not list FLUX.3; its FLUX rows are flux-2-pro at $0.0375 and flux-2-flex.

The grid

BFL sells credits at $0.01 each and publishes per-image prices by resolution. Sume's Seedream 5 Lite row is one number, so the same figure is used in each size row.

Why the grid is not a quality verdict

Seedream 5 Lite is priced flat on Sume while FLUX.3 scales with pixel count, so the gap grows as the size grows. This table cannot tell you whether the two models give the same output size for the same request. Check the model's capabilities from the Images API model list before you compare at a given size.

• At 768 by 768, FLUX.3 is the cheaper of the two by $0.00275 an image.
• The only FLUX row on Sume today is flux-2-pro at $0.0375, which is BFL's from-$0.03 FLUX.2 Pro rate times 1.25.
• Runway's API page also lists seedream5_lite, at 4 credits ($0.04) per image.

What to call on Sume

If you want a FLUX look now, flux-2-pro goes through the Images API with the usual job envelope. For FLUX.3, Sume's catalog has no row, so there is nothing to call by that name.

curl -X POST https://api.sume.com/v1/images \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: seedream-lite-001" \
  -d '{
    "model": "seedream-5-lite",
    "prompt": "Flat lay of a notebook and pen on a pale blue desk",
    "aspect_ratio": "1:1"
  }'

Verdict by budget

Under a $50 budget for 1,000 images, both models fit at the 1k size. Past 2k, Seedream 5 Lite's flat price is the cheaper line by a growing margin. If your output must be 4k, 1,000 FLUX.3 images are $607.00, so a 100-image test is $60.70.

A 200-image test run

A 200-image run at 2k is $20.00 on FLUX.3 Image and $8.75 on Seedream 5 Lite. At 1k it is $9.60 against $8.75. The difference is $0.85 at 1k and $11.25 at 2k, so the choice matters most when you ship above 1 megapixel. For 200 images at 768 by 768, FLUX.3 is $8.20 against $8.75.

BFL's page also lists FLUX.2 rows with from-prices: Pro from $0.03, Max from $0.07 and Flex from $0.05. Sume's flux-2-pro at $0.0375 is exactly $0.03 x 1.25, which suggests that Sume prices that row at the from-price.