FLUX 1.1 vs GPT Image 1.5: speed vs smarts

GPT Image 1.5 is the better pick when quality is the whole job: it sits at #2 overall on Infer's image leaderboard with 1271 Elo, and Infer's own benchmark copy credits it with 12% better photorealism than FLUX 1.1 [pro] and "Top 1" portrait fidelity (tryinfer.com/models/gpt-image-1-5). FLUX 1.1 [pro] wins when the job is volume: it generates in roughly 2.5 seconds against GPT Image 1.5's roughly 5, at $0.02/image against GPT Image 1.5's flat $0.04, though FLUX's own page also shows a conflicting $0.04/img mention elsewhere, a discrepancy Infer hasn't resolved. For a single hero image where composition has to hold up, use GPT Image 1.5. For a pipeline generating hundreds of variants a day, FLUX 1.1 [pro] does the job in half the time at up to half the price.

Infer hosts both models and takes no side in this; the ranking below follows the leaderboard and each model's own documented specs.

Spec comparison

Sources: tryinfer.com/models/flux-1-1-pro, tryinfer.com/models/gpt-image-1-5, tryinfer.com/leaderboards. Infer's full image-leaderboard table loads client-side and wasn't fully capturable in our latest data pull; the 1271 Elo figure for GPT Image 1.5 comes from its individual model page rather than a verified head-to-head snapshot against FLUX. Artificial Analysis runs a separate text-to-image arena that can diverge on a given day; its full table wasn't capturable in this pass either, so treat any cross-source Elo comparison as directional.

Scenario breakdown

High-volume ad-variant pipeline. Generating 200 variants of a product ad overnight is a throughput problem before it's a quality problem, and the math favors FLUX 1.1 [pro] on both axes: at ~2.5 seconds per image the batch clears in roughly 8 minutes versus GPT Image 1.5's ~5-second pace (about 17 minutes), and at $0.02/image it costs $4 for the run against GPT Image 1.5's $8 at its flat $0.04 rate. FLUX 1.1 [pro]'s documented use cases, high-volume creative pipelines, social/ad creative, e-commerce catalogs, target exactly this job, and it offers volume discounts at 10K requests/month on top.

Complex composed editorial scene. A packed frame with eight or more distinct elements, a market stall, a vendor, several customers, a cash register, a price sign, is the scenario Infer's own benchmark copy calls out for GPT Image 1.5 directly: it's positioned to hold together compositions of 8+ elements that trip up faster models. FLUX 1.1 [pro]'s Infer page doesn't make an equivalent multi-subject claim; its strengths are concept art and product imagery, not dense compositional scenes. On documented specs, this one goes to GPT Image 1.5.

Text-on-image marketing asset. A promotional graphic with a headline baked into the image favors GPT Image 1.5, which Infer lists directly for "text-on-image marketing" and calls a "strong second to Ideogram." FLUX 1.1 [pro]'s page makes no typography claim of any kind. Neither model is the dedicated pick here: Ideogram 3.0 is Infer's typography specialist at $0.06/image, but between these two, GPT Image 1.5 is the documented choice.

Run this prompt with FLUX 1.1 [pro] on Infer → · Test it with GPT Image 1.5 on Infer →

Where FLUX 1.1 [pro] wins

• Speed. ~2.5 seconds at default 4 steps, described on Infer as "6x faster" than FLUX.1 [pro], the older, non-Turbo version.
• Price, at its primary listed rate. $0.02/image against GPT Image 1.5's $0.04, plus volume discounts starting at 10K requests/month. (Confirm the live rate first; see the pricing discrepancy below.)
• Image-to-image. A straightforward init_image/strength parameter for iterating on an existing image, useful for the ad-variant and catalog work FLUX is built for.
• Volume-pipeline use cases. Concept art, social/ad creative, product imagery, and e-commerce catalogs are the exact jobs Infer lists it for.

FLUX 1.1 [pro]'s honest weak spot: Infer gives it no numeric leaderboard rank at all, and LoRA fine-tuning support is listed as "planned for roadmap," not shipped, so anything requiring a custom style or brand-specific fine-tune isn't available yet on this model.

Where GPT Image 1.5 wins

• Documented quality. #2 overall image on Infer's leaderboard at 1271 Elo, with a benchmark claim of 12% better photorealism than FLUX 1.1 [pro] and "Top 1" portrait fidelity.
• Dense, multi-subject compositions. Credited by Infer with holding together scenes of 8 or more elements, the threshold where faster models tend to merge objects.
• Text-on-image, as a secondary strength. Listed use case, positioned as a "strong second to Ideogram."
• Published rate limits at scale. 60 requests/minute by default, bursting to 120, scaling to 1,000+ rpm on paid tiers, a ceiling FLUX 1.1 [pro]'s page doesn't publish an equivalent for.

GPT Image 1.5's honest weak spot: at roughly 5 seconds per image and $0.04/image flat, it's both slower and (at FLUX's primary rate) twice the price for jobs where FLUX's documented output is already sufficient. That's a real cost in high-volume pipelines even though per-image it looks like a small number.

Pricing reality

A 1,000-image batch costs $20 with FLUX 1.1 [pro] at its primary $0.02/image rate, or $40 with GPT Image 1.5 at its flat $0.04/image: a straight 2x gap. But FLUX 1.1 [pro]'s own Infer page also references a separate $0.04/img figure elsewhere on the page, which, if that's the rate actually billed, erases the price advantage entirely. This is the one number in this comparison worth confirming on the live model page before committing a production budget to it; Infer hasn't reconciled the two figures as of this writing. Time compounds the gap regardless of which FLUX price applies: at ~2.5 seconds per image, that 1,000-image batch clears in about 42 minutes; at GPT Image 1.5's ~5 seconds, the same batch takes roughly 83 minutes. See more cost breakdowns on Infer's pricing hub.

The verdict

Choose FLUX 1.1 [pro] when the job is volume: ad variants, catalog batches, or any pipeline where speed and per-image cost compound across hundreds or thousands of renders. Just verify the live price first given the on-page discrepancy. Choose GPT Image 1.5 when a single image has to carry a lot: a packed editorial scene, a portrait that needs to hold up close, or a graphic with text baked in. And if the job is dedicated typography, a poster or logo where the lettering is the entire point, neither is the right call; Ideogram 3.0 is Infer's specialist for that at $0.06/image.

Try both side-by-side on Infer →

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See also: GPT Image 1.5 vs Nano Banana 2, the best text-to-image models in 2026, ranked, best AI models for product photography, Midjourney API alternatives, and the compare hub for every head-to-head we've run.