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GPT Image 2.5 Sunburstvs.Chroma1-Flash

Which one is better?

In our own test, GPT Image 2.5 Sunburst leads. Chroma1-Flash has no arena rating yet. Chroma1-Flash 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 Sunburst: Infographic, first image from the fixed test run
GPT Image 2.5 Sunburst97 out of 100
Chroma1-Flash: Infographic, first image from the fixed test run
Chroma1-Flash12 out of 100

Result for “Infographic”:GPT Image 2.5 Sunburst ahead

Prompt given to both modelsCreate a square German infographic titled SO FUNKTIONIERT PHOTOSYNTHESE. Show exactly four numbered steps in this order: 1 LICHT, 2 WASSER, 3 CO₂, 4 ZUCKER + SAUERSTOFF. Use a clean editorial science style with one plant cross-section, simple arrows, high contrast, legible labels, and no other text.

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.

Character and detail

GPT Image 2.5 Sunburst: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:51 PM. Source

Chroma1-Flash: manual, local PyTorch 2.13.0, Diffusers 0.36.0; lodestones/Chroma1-Flash@093c4f63b60507234aa53a073f1f9f565b3f4336; native 1024x1024, 1:1; one request, first output; steps=16, guidance=1.0, seed=1817192317085624771; mps for text encoder and denoising; cpu for native VAE decode; bfloat16 for text encoder and transformer; float32 for VAE, generated Nov 2, 2026, 8:25 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: 985a75b38642a9f0e5e0c0e0c67f1b7f67780d42bd2168fa24e9a7a7a94b0da6

GPT Image 2.5 Sunburst image SHA 256: 2bcd5e2358dbf9e2f11336ebf6c4a4a15e0a9a10261dd74378d40985ac68ec6d

Chroma1-Flash image SHA 256: e05e2caf9373cf90bfd96b30150729d99a9f58104437e9c38ea0543607b41190

Infographic

GPT Image 2.5 Sunburst: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:52 PM. Source

Chroma1-Flash: manual, local PyTorch 2.13.0, Diffusers 0.36.0; lodestones/Chroma1-Flash@093c4f63b60507234aa53a073f1f9f565b3f4336; native 1024x1024, 1:1; one request, first output; steps=16, guidance=1.0, seed=14241408974679486; mps for text encoder and denoising; cpu for native VAE decode; bfloat16 for text encoder and transformer; float32 for VAE, generated Nov 2, 2026, 8:27 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: ed65cb4e6a51e2336f8b149ad4cbb16e020f07d527ad94362e719d2dcf91d94f

GPT Image 2.5 Sunburst image SHA 256: 7dab94e5588be73aefe08f23f9d56ced4e2ddb2b29f754db41b057025cf34847

Chroma1-Flash image SHA 256: cf0f2160309bfc4bd6c00df8383d963af3fb1860cfa7509c6466f37afcb2bbc2

Product photography

GPT Image 2.5 Sunburst: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:51 PM. Source

Chroma1-Flash: manual, local PyTorch 2.13.0, Diffusers 0.36.0; lodestones/Chroma1-Flash@093c4f63b60507234aa53a073f1f9f565b3f4336; native 1024x1024, 1:1; one request, first output; steps=16, guidance=1.0, seed=4601939984165617850; mps for text encoder and denoising; cpu for native VAE decode; bfloat16 for text encoder and transformer; float32 for VAE, generated Nov 2, 2026, 8:24 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: c67fd71e91304458a2feef5c91efa8677260fab0c0099a29a2c52cb579f5b2f3

GPT Image 2.5 Sunburst image SHA 256: c648276704e06f7925f2325e8ffff0d9d0a9bd6c5bb4866785abac92ce97ff9a

Chroma1-Flash image SHA 256: 0c622731fd94810154ca50f7373f372c21911602c20b7cfd57451a77eb9fbbf0

Typography and layout

GPT Image 2.5 Sunburst: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:50 PM. Source

Chroma1-Flash: manual, local PyTorch 2.13.0, Diffusers 0.36.0; lodestones/Chroma1-Flash@093c4f63b60507234aa53a073f1f9f565b3f4336; native 1024x1024, 1:1; one request, first output; steps=16, guidance=1.0, seed=5666015459258575499; mps for text encoder and denoising; cpu for native VAE decode; bfloat16 for text encoder and transformer; float32 for VAE, generated Nov 2, 2026, 8:23 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: 2e012c3d14ee5dd02203a94f394ca80a5038cdebd6032b25a8b8a221f2255419

GPT Image 2.5 Sunburst image SHA 256: fd6a3767ba8253869cb94d5346f025541dac924c2190df2c37b366b182986cf8

Chroma1-Flash image SHA 256: 9729caf8c40b655d4fb8b8a9fc2437c099dce846a6a8367d79809dd8e08cfea9

The numbers at a glance

Arena ratingfrom votes by users · higher is better
1,427

GPT Image 2.5 Sunburst

Rank 1 of 21

n/a

Chroma1-Flash

not in the arena

GraduallyBenchour own rating, 0 to 100 · higher is better
75

GPT Image 2.5 Sunburst

Rank 8 of 108

24

Chroma1-Flash

Rank 92 of 108

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

GPT Image 2.5 Sunburst

expensive

n/a

Chroma1-Flash

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.

Chroma1-Flash

Subscription
n/a No plan in Germany names exactly this model.
Via API
No API price known. Access: local.
License
Open weights.

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 SunburstChroma1-Flash
Ratings
Arena ratingfrom votes by users, higher is better1,427n/a
Arena rankRank 1 of 21n/a
Arena votesmore votes, a safer rating54,913n/a
GraduallyBenchour own rating, 0 to 1007524
GraduallyBench by task
Typography and layoutLegible text, hierarchy, and composition5416
Product photographyMaterials, reflections, and fine details8716
Character and detailAnatomy, clothing, and spatial consistency6451
InfographicNumbers, labels, and visual organization9712
API price
Per imagelower is better$0.21n/a
100 images$21.07n/a
Profile
ReleasedSep 8, 2026n/a
Weightsopen means: runs locallyproprietaryopen
AccessAPIlocal
Parametersnot published8.9 billion
Largest output3,840 × 2,160 pixelsnot consistently published
Plans in Germanynaming exactly this model62n/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) · Chroma1-Flash model 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 Chroma1-Flash from the same arena and category. Older model versions are not used as substitutes.

More comparisons

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