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OpenAI · Language + Image model

GPT-5 Image Mini

openai/gpt-5-image-mini
  • Language
  • Image
Released Oct 16, 2025

GPT-5 Image Mini combines OpenAI's advanced language capabilities, powered by [GPT-5 Mini](https://openrouter.ai/openai/gpt-5-mini), with GPT Image 1 Mini for efficient image generation. This natively multimodal model features superior instruction following, text...

As a language model

Specifications

Context window
400,000 tokens
Max output
128,000 tokens
Input
file, image, text
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-mini","messages":[{"role":"user","content":"Hello"}],"max_tokens":300}'

As an image model

Specifications

Input
file, image, text
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-mini","prompt":"a lighthouse at dawn, 35mm film","aspect_ratio":"1:1"}'