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GPT Image 2.5 Flarevs.FLUX.2 Klein 9B Preview

Which one is better?

In our own test both are on par. 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.

GPT Image 2.5 Flare: Character and detail, first image from the fixed test run
GPT Image 2.5 Flare63 out of 100
FLUX.2 Klein 9B Preview: Character and detail, first image from the fixed test run
FLUX.2 Klein 9B Preview45 out of 100

Result for “Character and detail”:GPT Image 2.5 Flare slightly ahead

Prompt given to both modelsCreate a square cinematic full-body portrait of a fictional bicycle courier waiting under a transparent umbrella at a rainy tram stop in Hamburg at blue hour. She wears a mustard raincoat, navy trousers, red sneakers, a silver helmet, and carries a teal messenger bag. Keep both hands visible, render the bicycle correctly, use realistic wet-street reflections, and include no readable brand names.

What the rating looks at: Anatomy, clothing, and spatial consistency.

“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 Flare: 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 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 Flare image SHA 256: cc90d54a99e1bad9e0cc8e4196746fb1d56a2fdd2a9ee101dbbf270ef5e4b6a8

FLUX.2 Klein 9B Preview image SHA 256: 6cc5a70118def87bf0ec737b20c9dd56c3a7dd3ec776e007b8a5fdadd4c27849

Product photography

GPT Image 2.5 Flare: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:53 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 Flare image SHA 256: 69fedb7d635d1329c461ff1ee9e5cf8384119e218e3b3bdb93b9e11f728335d8

FLUX.2 Klein 9B Preview image SHA 256: b1f17cd46fcd8f8b862da7c59900c1616ac3db8052d92a344720b7dc7fcb75ea

Character and detail

GPT Image 2.5 Flare: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:53 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 Flare image SHA 256: 85b17c41b19389cae3ea073ef582e6065a321d741978e772987d22e3ea3e3b08

FLUX.2 Klein 9B Preview image SHA 256: 83bd206858a0d2bfab8a9d3bb7d90de6ff568017464a8168726175a6b324a90c

Infographic

GPT Image 2.5 Flare: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:53 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 Flare image SHA 256: bc752abfce1c0d27b73e4084c3e7d82c4c0f71e0e5af97a80f4b24326cc4686e

FLUX.2 Klein 9B Preview image SHA 256: deb8da580546e3d22e20222c5c7e8c1a95197f27be4bff0b064eba603bda7b47

The numbers at a glance

Arena ratingfrom votes by users · higher is better
1,399

GPT Image 2.5 Flare

Rank 2 of 21

n/a

FLUX.2 Klein 9B Preview

not in the arena

GraduallyBenchour own rating, 0 to 100 · higher is better
72

GPT Image 2.5 Flare

Rank 18 of 108

62

FLUX.2 Klein 9B Preview

Rank 48 of 108

Price per imagedollars through the API · lower is better
$0.21

GPT Image 2.5 Flare

expensive

n/a

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 Flare

Subscription
No OpenAI subscription includes this model. Through other providers from ≈ €6.36 a month (ElevenLabs Starter, with limited credits). 61 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.

KennzahlGPT Image 2.5 FlareFLUX.2 Klein 9B Preview
Ratings
Arena ratingfrom votes by users, higher is better1,399n/a
Arena rankRank 2 of 21n/a
Arena votesmore votes, a safer rating53,925n/a
GraduallyBenchour own rating, 0 to 1007262
GraduallyBench by task
Typography and layoutLegible text, hierarchy, and composition6456
Product photographyMaterials, reflections, and fine details6973
Character and detailAnatomy, clothing, and spatial consistency6345
InfographicNumbers, labels, and visual organization9175
API price
Per imagelower is better$0.21n/a
100 images$21.07n/a
Profile
ReleasedSep 8, 2026n/a
Weightsopen means: runs locallyproprietaryunknown
Lifecycleno noticePreview API route with newer quality/speed improvements; the stable 9B route remains separate
AccessAPIAPI
Parametersnot published9 billion
Largest outputnot consistently publishednot consistently published
Plans in Germanynaming exactly this model61n/a

API prices for one image at 1,024 × 1,024 pixels according to Artificial Analysis.

Sources: GPT Image 2.5 Flare model source (verified Sep 22, 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 Flare 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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