OpenAI · Language + Image model

GPT-5 Image

openai/gpt-5-image

Language
Image

Released Oct 14, 2025

[GPT-5](https://openrouter.ai/openai/gpt-5) Image combines OpenAI's GPT-5 model with state-of-the-art image generation capabilities. It offers major improvements in reasoning, code quality, and user experience while incorporating GPT Image 1's superior instruction following,...

As a language model

Specifications

Context window: 400,000 tokens
Max output: 128,000 tokens
Input: image, text, file
Output: image, text
Reasoning: always on
Tokenizer: GPT
Moderation: provider-moderated

Supported parameters

Accepted by the model and forwarded as-is by the gateway.

frequency_penalty
logit_bias
logprobs
max_tokens
presence_penalty
reasoning
response_format
seed
stop
structured_outputs
temperature
top_logprobs
top_p

Use it

POST /api/v1/chat/completions · MCP chat · full reference

curl https://omnirail.org/api/v1/chat/completions \
  -H "Authorization: Bearer $OMNIRAIL_KEY" -H "Content-Type: application/json" \
  -d '{"model":"openai/gpt-5-image","messages":[{"role":"user","content":"Hello"}],"max_tokens":300}'

As an image model

Specifications

Input: image, text, file
Output: image, text
Editing: yes, up to 16 reference images
Images per call: 1 to 4
Served by: OpenAI

Request options

Validated against these values; anything else returns 400 with the allowed list.

aspect_ratio: 1:1, 3:2, 2:3, auto
quality: auto, low, medium, high
background: auto, transparent, opaque
output_compression: 0 to 100

Use it

POST /api/v1/images · /images/edits · MCP generate_image · edit_image · full reference

curl https://omnirail.org/api/v1/images \
  -H "Authorization: Bearer $OMNIRAIL_KEY" -H "Content-Type: application/json" \
  -d '{"model":"openai/gpt-5-image","prompt":"a lighthouse at dawn, 35mm film","aspect_ratio":"1:1"}'