"Best AI image generation API" has no single answer — it depends on whether you are rendering 10,000 catalog thumbnails or one brand-critical hero. What you actually want is one integration that gives you the right model for each job. hiapi ships a roster of image models behind a single unified task API, so the question becomes practical: which model, for which job, at what price. This guide gives you the live pricing, a same-prompt head-to-head across three models, and a use-case shortlist.
All prices below are the live per-image rates on hiapi (1K resolution), verified against the platform's pricing.
The image model lineup, by price
| Model | Per 1K image | Best for |
|---|---|---|
| flux-schnell | $0.005 | Cheapest tier — bulk drafts, thumbnails, fast iteration |
| z-image | $0.008 | Ultra-low-cost general generation |
| gpt-image-2-beta | $0.02 | Preview tier of GPT Image 2 |
| qwen-image-2.0 | $0.025 | Chinese / bilingual text rendering |
| gpt-image-2 | $0.03 | Default: instruction-following, on-image text, products |
| flux-1.1-pro | $0.05 | Photoreal portraits, dramatic lighting |
| flux-2/text-to-image | $0.05 | High prompt adherence, in-image text |
| Nano-Banana | $0.05 | Gemini-based general image model |
| Nano-Banana-2 | $0.085 | Polished marketing composites |
| Nano-Banana-Pro | $0.17 | High-resolution Gemini 3 Pro tier |
| gpt-image-2-pro | $0.35 | Stability tier for high-stakes production |
The spread is 70× from floor to ceiling — which is exactly why picking per-job matters. Iterate on a $0.005 model, ship on the one that fits the brief.
Same prompt, three models
To make the differences concrete, here is one identical prompt — a fitness-app poster with a headline MOVE DAILY and a tagline Your day, in motion — run through three models. The prompt deliberately demands on-image text, which is where models diverge most.
gpt-image-2 — $0.03
Crisp headline, a fully legible in-app dashboard (rings, stats, a feature row), and a clean tagline. Strong instruction-following and the most reliable text of the three. Task tk-hiapi-01KVQK96GYV2GTN9BVYGDD3AK7.
Nano-Banana-2 — $0.085
The most polished composite — clean headline and tagline, a detailed device mockup, and it even added a tidy "DOWNLOAD NOW" call-to-action. The premium-marketing pick when the layout has to look finished. Task tk-hiapi-01KVQKCSYSSF4FB687R9Q08T3N.
flux-1.1-pro — $0.05
The headline MOVE DAILY is clean, but the secondary copy below the tagline came out garbled — the classic FLUX trade-off. FLUX 1.1 Pro is a photoreal powerhouse for portraits and lighting, but it is the weakest of the three on dense in-image text. Task tk-hiapi-01KVQKC5CKWFTJ66K0NJHHMGBY.
Read: for anything with copy — posters, ads, packaging, UI mockups — gpt-image-2 and Nano-Banana-2 are the safe picks; gpt-image-2 wins on price. Reach for FLUX 1.1 Pro when the job is photoreal imagery, not text.
Pick by use case
- Default / products / on-image text →
gpt-image-2($0.03). Best price-to-instruction-following ratio. - Polished marketing composites →
Nano-Banana-2($0.085) when the layout must look finished out of the box. - Photoreal portraits, dramatic lighting →
flux-1.1-pro($0.05). - Chinese / bilingual signage and posters →
qwen-image-2.0($0.025). - Bulk drafts and thumbnails →
flux-schnell($0.005) orz-image($0.008). - High-stakes, stability-first production →
gpt-image-2-pro($0.35).
For deeper one-on-one comparisons, see GPT Image 2 vs FLUX 1.1 Pro and GPT Image 2 vs Nano Banana 2. Every model here speaks the same hiapi task API, so switching is a one-line change to the model field — start on the GPT Image 2 model page and branch out as your jobs demand.
