aicentosNano Banana 2 Image Generation
Generate images with gemini-3.1-flash-image-preview (Nano Banana 2) via aicentos — examples for the Gemini native format and the OpenAI-compatible format
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This page shows request examples for generating images with Nano Banana 2 (gemini-3.1-flash-image-preview) through aicentos. Both the Gemini native format and the OpenAI-compatible format are supported.
Through imageConfig you can specify the aspect ratio (aspectRatio) and resolution (imageSize, e.g. 2K, 4K).
Gemini native format
Generate a 1:1 4K image:
export AICENTOS_API_KEY="sk-your-API-Key"
curl --location --request POST 'https://aicentos.com/v1beta/models/gemini-3.1-flash-image-preview:generateContent' \
--header "x-goog-api-key: $AICENTOS_API_KEY" \
--header 'content-type: application/json' \
--header 'Accept: */*' \
--data-raw '{
"contents": [
{
"parts": [
{
"text": "Retro promotional poster style, highlighting Chinese text, with a red and yellow radial burst background. At the center, a beautiful young woman drawn in a refined vintage style, smiling, elegant and approachable. The theme is an ad promotion for the latest AI painting service, 4K resolution\n"
}
]
}
],
"generationConfig": {
"responseModalities": [
"image"
],
"imageConfig": {
"aspectRatio": "1:1",
"imageSize": "4K"
}
}
}'OpenAI-compatible format
Generate a 9:16 2K image:
export AICENTOS_API_KEY="sk-your-API-Key"
curl --location --request POST 'https://aicentos.com/v1/chat/completions' \
--header "Authorization: Bearer $AICENTOS_API_KEY" \
--header 'Content-Type: application/json' \
--header 'Accept: */*' \
--data-raw '{
"model": "gemini-3.1-flash-image-preview",
"extra_body": {
"imageConfig": {
"aspectRatio": "9:16",
"imageSize": "2K"
}
},
"messages": [
{
"role": "system",
"content": "{\"imageConfig\": {\"aspectRatio\": \"9:16\", \"imageSize\": \"2K\"}}"
},
{
"role": "user",
"content": [
{
"type": "text",
"text": "Draw an auspicious Year of the Horse"
}
]
}
],
"max_tokens": 4096,
"temperature": 0.8
}'Parameters
aspectRatio: aspect ratio, e.g.1:1,9:16,16:9.imageSize: resolution, e.g.2K,4K.- The Gemini native format authenticates with
x-goog-api-key; the OpenAI-compatible format authenticates withAuthorization: Bearer. - In the OpenAI-compatible format,
imageConfigcan go either inextra_bodyor in the JSON of thesystemmessage. - Replace
sk-your-API-Keyin the examples with the API Key you created in the aicentos console.