GPT Image 2 / 2.5 Image Generation API

¶ 1. Obtain an API Key

Open the 费思量-API application list, enter an available application, and copy the API Key.

¶ 2. Send the First Request

curl https://api.fesilent.com/openai/images/generations \
  -H "Authorization: Bearer 你的 API Key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-image-2",
    "prompt": "Minimal editorial product illustration: one plain white ceramic coffee mug centered on a solid cobalt blue tabletop, pale cream background, soft shadow, clean geometric shapes, no text, no logo, portrait composition",
    "size": "1024x1536"
  }'

The image in a successful response is located at data[].url. Below is the actual 1024×1536 result obtained through an 费思量-API request on September 8, 2026 (task d56455e2-e7f7-4bcd-b935-475b0a1e0948, trace eb938601-8192-407f-b539-1e0554b697ec):

¶ 3. Common Parameters

Field	Description
model	gpt-image-2 (recommended by default), gpt-image-2.5-flare (faster), or gpt-image-2.5-sunburst (higher fidelity and control); all three can use their corresponding :official variants, and gpt-image-2 also supports :reverse
prompt	Image description, up to 32,000 characters
size	auto or WIDTHxHEIGHT; width and height must be multiples of 16, the longest side must not exceed 3840, total pixels must be 655,360–8,294,400, and the aspect ratio must not exceed 3:1
n	1–10; only 1 is supported when response_format=b64_json
quality	low, medium, high, or auto; support and billing methods vary across routes
response_format	url or b64_json
callback_url	Optional; sends results to this address after a long-running task is completed

Common sizes:

Ratio	1K	2K	4K
1:1	1024x1024	2048x2048	2880x2880
4:3	1536x1024	2048x1536	3264x2448
3:4	1024x1536	1536x2048	2448x3264
16:9	1792x1024	2048x1152	3840x2160
9:16	1024x1792	1152x2048	2160x3840

size: "auto" selects the canvas according to the ratio, pixels, and layout intent in the prompt; directly specify dimensions when exact pixels are required.

¶ Models and Billing Methods

Model	Applicable Scenarios and Billing Methods
gpt-image-2	Default reverse route, billed at a fixed rate per successfully generated image
gpt-image-2:reverse	Explicitly selects the reverse route, billed at a fixed rate per successfully generated image
gpt-image-2:official	Official API route, with higher stability, billed by actual Token usage
gpt-image-2.5-flare	Focuses on generation speed, billed at a fixed rate per successfully generated image
gpt-image-2.5-flare:official	Official API route, with higher stability and a focus on generation speed, billed by actual Token usage
gpt-image-2.5-sunburst	Focuses on high fidelity and fine-grained control, billed at a fixed rate per successfully generated image
gpt-image-2.5-sunburst:official	Official API route, with higher stability and a focus on high fidelity and fine-grained control, billed by actual Token usage

The displayed prices for the official API route are estimates before the request; the final amount is based on the actual Token usage in the response and usage records.

¶ 4. Multiple Image Generation

curl https://api.fesilent.com/openai/images/generations \
  -H "Authorization: Bearer 你的 API Key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-image-2",
    "prompt": "A small fox reading under a glowing mushroom, watercolor illustration",
    "size": "1536x1024",
    "n": 2
  }'

gpt-image-2, gpt-image-2.5-flare, gpt-image-2.5-sunburst, and gpt-image-2:reverse are billed by the number of successfully generated images; gpt-image-2:official, gpt-image-2.5-flare:official, and gpt-image-2.5-sunburst:official are billed according to the actual text input and image output Tokens in the response. Displayed prices are estimates before the request; the final amount is based on usage records.

¶ 5. Asynchronous Callback

After adding callback_url to the request body, the API first returns {"task_id": "..."} and POSTs the final result to that URL upon completion; synchronous requests still return created and data:

{
  "model": "gpt-image-2",
  "prompt": "A product poster with clear typography",
  "size": "1024x1024",
  "callback_url": "https://example.com/webhooks/images"
}

The callback receiver should use task_id for deduplication and validate the request source and data format.

¶ 6. Troubleshooting

Status	Check
400	The combination of model, prompt, size format, n, and response_format
401	Whether the API Key is complete and whether the Header is Authorization: Bearer ...
429	Requests are too frequent; retry later
504	Synchronous generation timed out; use callback_url

Error responses include error.code, error.message, and trace_id. Provide trace_id when reporting an issue, and do not provide the API Key.

For complete fields and real-time enums, refer to the OpenAI Images Generations API page. For image editing, see GPT Image 2 / 2.5 Image Editing.