GPT Image 2.5 Sunburstvs.FLUX.2 Klein 9B Preview
Which one is better?
In our own test, GPT Image 2.5 Sunburst leads. FLUX.2 Klein 9B Preview has no arena rating yet. FLUX.2 Klein 9B Preview has no API price.
Test images
Same task, the first image of each. The task with the biggest difference is preselected.
Result for “Infographic”:GPT Image 2.5 Sunburst ahead
What the rating looks at: Numbers, labels, and visual organization.
“Ahead”: better in all three rating rounds. “Slightly ahead”: a higher value, but not in every round.
Test protocol of the images
Each test attempt uses the same archived prompt and one request. The first output of that attempt counts. Repeats after technical test failures are disclosed for the affected images. Files are normalized to 1,024 × 1,024 pixels without cropping. Provider resolution, randomness, quality tier and prompt processing can still differ. The images are a practical visual test, not a reconstruction of the arena configuration.
Typography and layout
GPT Image 2.5 Sunburst: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:50 PM. Source
FLUX.2 Klein 9B Preview: manual, BFL API /v1/flux-2-klein-9b-preview (distinct preview checkpoint); native 1024x1024, 1:1; one request per attempt; two submissions; original signed output expired after local retrieval failure; first output of technical repeat with unchanged prompt and seed; seed=4230828387; output_format=png; no reference images or negative prompt, generated Nov 2, 2026, 7:06 PM. Source
Protocol gradually-image-comparison-v1. Prompt SHA 256: 2e012c3d14ee5dd02203a94f394ca80a5038cdebd6032b25a8b8a221f2255419
GPT Image 2.5 Sunburst image SHA 256: fd6a3767ba8253869cb94d5346f025541dac924c2190df2c37b366b182986cf8
FLUX.2 Klein 9B Preview image SHA 256: 6cc5a70118def87bf0ec737b20c9dd56c3a7dd3ec776e007b8a5fdadd4c27849
Product photography
GPT Image 2.5 Sunburst: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:51 PM. Source
FLUX.2 Klein 9B Preview: manual, BFL API /v1/flux-2-klein-9b-preview (distinct preview checkpoint); native 1024x1024, 1:1; one request, first output; seed=132780547; output_format=png; no reference images or negative prompt; first provider output recovered by GET after local regional API validation stopped polling; no regeneration, generated Nov 2, 2026, 7:04 PM. Source
Protocol gradually-image-comparison-v1. Prompt SHA 256: c67fd71e91304458a2feef5c91efa8677260fab0c0099a29a2c52cb579f5b2f3
GPT Image 2.5 Sunburst image SHA 256: c648276704e06f7925f2325e8ffff0d9d0a9bd6c5bb4866785abac92ce97ff9a
FLUX.2 Klein 9B Preview image SHA 256: b1f17cd46fcd8f8b862da7c59900c1616ac3db8052d92a344720b7dc7fcb75ea
Character and detail
GPT Image 2.5 Sunburst: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:51 PM. Source
FLUX.2 Klein 9B Preview: manual, BFL API /v1/flux-2-klein-9b-preview (distinct preview checkpoint); native 1024x1024, 1:1; one request, first output; seed=3453819885; output_format=png; no reference images or negative prompt, generated Nov 2, 2026, 7:05 PM. Source
Protocol gradually-image-comparison-v1. Prompt SHA 256: 985a75b38642a9f0e5e0c0e0c67f1b7f67780d42bd2168fa24e9a7a7a94b0da6
GPT Image 2.5 Sunburst image SHA 256: 2bcd5e2358dbf9e2f11336ebf6c4a4a15e0a9a10261dd74378d40985ac68ec6d
FLUX.2 Klein 9B Preview image SHA 256: 83bd206858a0d2bfab8a9d3bb7d90de6ff568017464a8168726175a6b324a90c
Infographic
GPT Image 2.5 Sunburst: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:52 PM. Source
FLUX.2 Klein 9B Preview: manual, BFL API /v1/flux-2-klein-9b-preview (distinct preview checkpoint); native 1024x1024, 1:1; one request, first output; seed=1679342581; output_format=png; no reference images or negative prompt, generated Nov 2, 2026, 7:06 PM. Source
Protocol gradually-image-comparison-v1. Prompt SHA 256: ed65cb4e6a51e2336f8b149ad4cbb16e020f07d527ad94362e719d2dcf91d94f
GPT Image 2.5 Sunburst image SHA 256: 7dab94e5588be73aefe08f23f9d56ced4e2ddb2b29f754db41b057025cf34847
FLUX.2 Klein 9B Preview image SHA 256: deb8da580546e3d22e20222c5c7e8c1a95197f27be4bff0b064eba603bda7b47
The numbers at a glance
GPT Image 2.5 Sunburst
Rank 1 of 21
FLUX.2 Klein 9B Preview
not in the arena
GPT Image 2.5 Sunburst
Rank 8 of 108
FLUX.2 Klein 9B Preview
Rank 48 of 108
GPT Image 2.5 Sunburst
expensive
FLUX.2 Klein 9B Preview
no API price
Ranks among the 21 image models with an arena rating and the 108 with a GraduallyBench run; prices compared with 28 models with an API price.
GPT Image 2.5 Sunburst
- Subscription
- No OpenAI subscription includes this model. Through other providers from ≈ €6.36 a month (ElevenLabs Starter, with limited credits). 62 plans in Germany.
- Via API
- $0.21 per image, 100 images $21.07.
FLUX.2 Klein 9B Preview
- Subscription
- n/a No plan in Germany names exactly this model.
- Via API
- No API price known. Access: API.
- Weights
- unknown.
Subscriptions only count plans that name exactly this model. Subscription prices include VAT, API prices are in dollars.
Arena rating (LMArena) from Nov 6, 2026 · GraduallyBench from Nov 3, 2026 · API prices from Nov 6, 2026 · Subscription database from Sep 29, 2026 (38 days old)
All data side by side
The better value is bold. For ratings only when the gap is clear.
| Kennzahl | GPT Image 2.5 Sunburst | FLUX.2 Klein 9B Preview |
|---|---|---|
| Ratings | ||
| Arena ratingfrom votes by users, higher is better | 1,427 | n/a |
| Arena rank | Rank 1 of 21 | n/a |
| Arena votesmore votes, a safer rating | 54,913 | n/a |
| GraduallyBenchour own rating, 0 to 100 | 75 | 62 |
| GraduallyBench by task | ||
| Typography and layoutLegible text, hierarchy, and composition | 54 | 56 |
| Product photographyMaterials, reflections, and fine details | 87 | 73 |
| Character and detailAnatomy, clothing, and spatial consistency | 64 | 45 |
| InfographicNumbers, labels, and visual organization | 97 | 75 |
| API price | ||
| Per imagelower is better | $0.21 | n/a |
| 100 images | $21.07 | n/a |
| Profile | ||
| Released | Sep 8, 2026 | n/a |
| Weightsopen means: runs locally | proprietary | unknown |
| Lifecycle | no notice | Preview API route with newer quality/speed improvements; the stable 9B route remains separate |
| Access | API | API |
| Parameters | not published | 9 billion |
| Largest output | 3,840 × 2,160 pixels | not consistently published |
| Plans in Germanynaming exactly this model | 62 | n/a |
API prices for one image at 1,024 × 1,024 pixels according to Artificial Analysis.
Sources: GPT Image 2.5 Sunburst model source (verified Sep 24, 2026) · FLUX.2 Klein 9B Preview model source, status source (verified Nov 1, 2026)
Arena ratings by category
From blind votes on LMArena. “Ahead” means the lead is clear.
No shared arena score in the stored snapshot
The stored benchmark database contains no measurement for GPT Image 2.5 Sunburst and FLUX.2 Klein 9B Preview from the same arena and category. Older model versions are not used as substitutes.
More comparisons
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