GPT-Image-2 image generation

• Model: gpt-image-2
• Endpoint: POST https://apimaster.ai/v1/images/generations
• Mode: Async — returns task_id, then poll the task
• Features: Text-to-image; image-to-image with up to 16 reference images (URL + base64 mix)

Auth

Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

Body parameters

Field	Type	Required	Notes
model	string	yes	gpt-image-2
prompt	string	yes	Scene description; safety moderation applies
n	integer	no	1 only (numeric, no quotes)
size	string	no	Aspect ratio, default 1:1
resolution	string	no	1k / 2k / 4k, default 1k
image_urls	array	no	Reference images → image-to-image
official_fallback	boolean	no	Official channel fallback, default false

size values

auto, 1:1, 3:2, 2:3, 4:3, 3:4, 5:4, 4:5, 16:9, 9:16, 2:1, 1:2, 3:1, 1:3, 21:9, 9:21, or pixel strings like 3840x2160.

resolution (sample pixels)

size	1k	2k	4k
1:1	1024×1024	2048×2048	2880×2880
16:9	1536×864	2048×1152	3840×2160

All 15 ratios support 4K.

image_urls

• Max 16 images
• Public URLs and base64 data URIs can be mixed
• Omit size to follow input resolution; set size to force output aspect ratio

Examples

Minimal text-to-image

{
  "model": "gpt-image-2",
  "prompt": "An orange cat on a windowsill at sunset, watercolor"
}

16:9 @ 2K

curl -s "https://apimaster.ai/v1/images/generations" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-image-2",
    "prompt": "a corgi astronaut on the moon, cinematic",
    "size": "16:9",
    "resolution": "2k"
  }'

Submit response

{
  "code": 200,
  "data": [{ "status": "submitted", "task_id": "task_01KPQ7J7DWB7QZ3WCEK3YVPBRA" }]
}

HTTP	Meaning
400	Invalid parameters
401	Bad API key
402	Insufficient balance
429	Rate limited

Poll task result

curl -s "https://apimaster.ai/v1/tasks/TASK_ID" \
  -H "Authorization: Bearer YOUR_API_KEY"

Image URL: data.result.images[0].url[0]

status	Meaning
submitted	Queued
processing	Running
completed	Ready
failed	See error

Poll after 10–20s, every 3–5s. Batch: POST https://apimaster.ai/v1/tasks/batch with {"task_ids":[...]}.

Notes

• Async only — no synchronous image URL in the create response.
• Prefer size for aspect ratio; avoid repeating ratio in prompt.
• Billing by resolution tier; see console for your account.

Compare with official channel.