Stable Diffusion 3.5 Largevs.GPT Image 2.5 Flare

Which one is better?

GPT Image 2.5 Flare leads in both ratings: in our own test and in the arena. Stable Diffusion 3.5 Large has no API price.

Test images

Same task, the first image of each. The task with the biggest difference is preselected.

Stable Diffusion 3.5 Large: Product photography, first image from the fixed test run — Stable Diffusion 3.5 Large17 out of 100

GPT Image 2.5 Flare: Product photography, first image from the fixed test run — GPT Image 2.5 Flare69 out of 100

Result for “Product photography”:GPT Image 2.5 Flare ahead

Prompt given to both modelsCreate a square premium product photograph of a brushed titanium wristwatch standing upright on dark green marble. The watch has a cream dial, thin black hands set to 10:10, twelve distinct hour markers, a realistic crown, and a dark brown leather strap. Soft window light from the left, controlled reflections, shallow depth of field, no text, no logo, no extra objects.

What the rating looks at: Materials, reflections, and fine details.

“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

Stable Diffusion 3.5 Large: fal, requested 1024x1024, n=1, seed=7087247023770270000, estimated cost $0.068157, generated Aug 14, 2026, 2:37 PM. Source

GPT Image 2.5 Flare: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:53 PM. Source

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

Stable Diffusion 3.5 Large image SHA 256: e748006fe56e442ad347e3f994f18b86ee1739f20dcee063aa7a03ee710c5d54

GPT Image 2.5 Flare image SHA 256: 85b17c41b19389cae3ea073ef582e6065a321d741978e772987d22e3ea3e3b08

Infographic

Stable Diffusion 3.5 Large: fal, requested 1024x1024, n=1, seed=12166653711354006000, estimated cost $0.068157, generated Aug 14, 2026, 2:37 PM. Source

GPT Image 2.5 Flare: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:53 PM. Source

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

Stable Diffusion 3.5 Large image SHA 256: 4eb0fd741ef42e6d3fee4b1280cdfb098a0a04009b139051963895892e349f1e

GPT Image 2.5 Flare image SHA 256: bc752abfce1c0d27b73e4084c3e7d82c4c0f71e0e5af97a80f4b24326cc4686e

Product photography

Stable Diffusion 3.5 Large: fal, requested 1024x1024, n=1, seed=13346308312015933000, estimated cost $0.068157, generated Aug 14, 2026, 2:37 PM. Source

GPT Image 2.5 Flare: openai, 1024x1024, quality high, n=1, generated Sep 28, 2026, 8:53 PM. Source

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

Stable Diffusion 3.5 Large image SHA 256: ea9a7401dee8859ec2cb96af9f7ca29a177ef2202f52f629d8ce9f5839bd4061

GPT Image 2.5 Flare image SHA 256: 69fedb7d635d1329c461ff1ee9e5cf8384119e218e3b3bdb93b9e11f728335d8

Typography and layout

Stable Diffusion 3.5 Large: fal, requested 1024x1024, n=1, seed=16632333557910893000, estimated cost $0.068157, generated Aug 14, 2026, 2:37 PM. Source

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

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

Stable Diffusion 3.5 Large image SHA 256: e2994b1883a245b1c8c447957d121ea89d93aafff149029aa4e8507dbb769f9a

GPT Image 2.5 Flare image SHA 256: cc90d54a99e1bad9e0cc8e4196746fb1d56a2fdd2a9ee101dbbf270ef5e4b6a8

The numbers at a glance

Arena ratingfrom votes by users · higher is better

938

Stable Diffusion 3.5 Large

Rank 21 of 21

1,401

GPT Image 2.5 Flare

Rank 2 of 21

GraduallyBenchour own rating, 0 to 100 · higher is better

Stable Diffusion 3.5 Large

Rank 87 of 108

GPT Image 2.5 Flare

Rank 18 of 108

Price per imagedollars through the API · lower is better

n/a

Stable Diffusion 3.5 Large

no API price

$0.21

GPT Image 2.5 Flare

expensive

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.

Stable Diffusion 3.5 Large

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

GPT Image 2.5 Flare

Subscription: No OpenAI subscription includes this model. Through other providers from ≈ €6.34 a month (ElevenLabs Starter, with limited credits). 61 plans in Germany.
Via API: $0.21 per image, 100 images $21.07.

Subscriptions only count plans that name exactly this model. Subscription prices include VAT, API prices are in dollars.

Arena rating (LMArena) from Oct 28, 2026 · GraduallyBench from Nov 3, 2026 · API prices from Nov 3, 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	Stable Diffusion 3.5 Large	GPT Image 2.5 Flare
Ratings
Arena ratingfrom votes by users, higher is better	938	1,401
Arena rank	Rank 21 of 21	Rank 2 of 21
Arena votesmore votes, a safer rating	23,396	39,218
GraduallyBenchour own rating, 0 to 100	27	72
GraduallyBench by task
Typography and layoutLegible text, hierarchy, and composition	31	64
Product photographyMaterials, reflections, and fine details	17	69
Character and detailAnatomy, clothing, and spatial consistency	23	63
InfographicNumbers, labels, and visual organization	39	91
API price
Per imagelower is better	n/a	$0.21
100 images	n/a	$21.07
Profile
Released	Oct 22, 2024	Sep 8, 2026
Weightsopen means: runs locally	open	proprietary
Access	API, local	API
Parameters	8.1 billion	not published
Largest output	1 Megapixel	not consistently published
Plans in Germanynaming exactly this model	n/a	61

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

Sources: Stable Diffusion 3.5 Large model source (verified Aug 15, 2026) · GPT Image 2.5 Flare model source (verified Sep 22, 2026)

Arena ratings by category

From blind votes on LMArena. “Ahead” means the lead is clear.

Arena rating per categoryfrom votes by users · higher is betterStable Diffusion 3.5 LargeGPT Image 2.5 Flare

Text to Image: 3D modeling9631,378ahead

Text to Image: Art9971,387ahead

Text to Image: Cartoon9451,431ahead

Text to Image: Commercial design9371,387ahead

Text to Image: Overall9381,401ahead

Text to Image: Photorealism9281,415ahead

Text to Image: Portraits9421,439ahead

Text to Image: Text rendering9211,435ahead

LMArena from Oct 28, 2026

All individual values with sources

Rating	Stable Diffusion 3.5 Large	GPT Image 2.5 Flare	Source
Text to Image: 3D modeling	963	1,378	LMArenaRetrieved Oct 28, 2026
Text to Image: Art	997	1,387	LMArenaRetrieved Oct 28, 2026
Text to Image: Cartoon	945	1,431	LMArenaRetrieved Oct 28, 2026
Text to Image: Commercial design	937	1,387	LMArenaRetrieved Oct 28, 2026
Text to Image: Overall	938	1,401	LMArenaRetrieved Oct 28, 2026
Text to Image: Photorealism	928	1,415	LMArenaRetrieved Oct 28, 2026
Text to Image: Portraits	942	1,439	LMArenaRetrieved Oct 28, 2026
Text to Image: Text rendering	921	1,435	LMArenaRetrieved Oct 28, 2026

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Predecessor and successor

Stable Diffusion 3.5 Large has no successor yet
No predecessor recorded for GPT Image 2.5 Flare
GPT Image 2.5 Flare has no successor yet

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