Imagen 4 Fast vs FLUX.2 [pro]
Google's Imagen 4 Fast and Black Forest Labs's FLUX.2 [pro] both target image generation, but they price and behave differently. Here is the side-by-side.
Pricing checked against provider documentation on . How we verify
The short answer
Imagen 4 Fast is the cheaper option — roughly 1.5x less on a blended workload, and it suits cheapest speed-first generation. FLUX.2 [pro] justifies its premium when you need cheapest flagship-tier image quality.
Google • Imagen 4
$0.02 / $
/ image (input / output)
Google's efficiency tier for image generation, aimed at high-volume pipelines where throughput matters more than the last increment of quality. Fine for thumbnails, placeholders, and drafts; step up to the Gemini image models when typography or compositing is the point.
Black Forest Labs • FLUX.2
$0.03 / $
/ image (input / output)
The best quality-per-dollar in hosted image generation, at three cents for a 1024² render through the official API, fal.ai, or Replicate alike. Note that Replicate prices by megapixel, so feeding in reference images for an edit pushes a single call closer to $0.055.
Input price
FLUX.2 [pro] is 50% more expensive than Imagen 4 Fast on input tokens.
Specification comparison
| Attribute | Imagen 4 Fast | FLUX.2 [pro] |
|---|---|---|
| Input (/ image) | $0.02 | $0.03 |
| Output (/ image) | — | — |
| Cached input | — | — |
| Context window | — | — |
| Max output | — | — |
| Native reasoning | No | No |
| Knowledge cutoff | — | — |
| Relative latency | low | low |
| Open weights | No | No |
| API model ID | imagen-4.0-fast-generate-001 | flux-2-pro |
| Status | stable | stable |
Imagen 4 Fast: 1K resolution.
FLUX.2 [pro]: 1024² generation. The [pro] tier is API-only; FLUX's smaller schnell and dev variants are the openly downloadable ones.
Choose Imagen 4 Fast if…
- High-volume thumbnails
- Draft and placeholder imagery
- Rapid prompt iteration
- Catalogue and listing images
Choose FLUX.2 [pro] if…
- Production creative at volume
- Image-to-image editing
- E-commerce and catalogue art
- Design exploration
Frequently asked
Is Imagen 4 Fast or FLUX.2 [pro] cheaper?
Imagen 4 Fast is cheaper. On a blended 3:1 input-to-output workload it costs about 1.5x less than FLUX.2 [pro].
Which has the larger context window, Imagen 4 Fast or FLUX.2 [pro]?
Both accept up to — tokens, so context is not a differentiator here.
Should I use Imagen 4 Fast or FLUX.2 [pro]?
Pick Imagen 4 Fast for cheapest speed-first generation. Pick FLUX.2 [pro] for cheapest flagship-tier image quality. If cost dominates the decision, Imagen 4 Fast wins; if you need the capability ceiling, benchmark both on your own evals before committing.