Image Generation
Knox supports image generation through models that have "image" in their output_modalities. These models can create images from text prompts when you specify the appropriate modalities in your request.
Model Discovery
You can find image generation models in several ways:
On the Models Page
Visit the Models List and filter by output modalities to find models capable of image generation. Look for models that list "image" in their output modalities.
In the Chatroom
When using the Chat, click the Image button to automatically filter and select models with image generation capabilities. If no image-capable model is active, you'll be prompted to add one.
API Usage
To generate images, send a request to the /v1/chat/completions endpoint with the modalities parameter set to include both "image" and "text".
Basic Image Generation
- Python
- TypeScript
import requests
import json
url = "https://api.knox.chat/v1/chat/completions"
headers = {
"Authorization": f"Bearer {API_KEY_REF}",
"Content-Type": "application/json"
}
payload = {
"model": "google/gemini-2.5-flash-image",
"messages": [
{
"role": "user",
"content": "Generate a beautiful sunset over mountains"
}
],
"modalities": ["image", "text"]
}
response = requests.post(url, headers=headers, json=payload)
result = response.json()
# The generated image will be in the assistant message
if result.get("choices"):
message = result["choices"][0]["message"]
if message.get("images"):
for image in message["images"]:
image_url = image["image_url"]["url"] # Base64 data URL
print(f"Generated image: {image_url[:50]}...")
const response = await fetch('https://api.knox.chat/v1/chat/completions', {
method: 'POST',
headers: {
Authorization: `Bearer ${API_KEY_REF}`,
'Content-Type': 'application/json',
},
body: JSON.stringify({
model: '{{MODEL}}',
messages: [
{
role: 'user',
content: 'Generate a beautiful sunset over mountains',
},
],
modalities: ['image', 'text'],
}),
});
const result = await response.json();
// The generated image will be in the assistant message
if (result.choices) {
const message = result.choices[0].message;
if (message.images) {
message.images.forEach((image, index) => {
const imageUrl = image.image_url.url; // Base64 data URL
console.log(`Generated image ${index + 1}: ${imageUrl.substring(0, 50)}...`);
});
}
}
Streaming Image Generation
Image generation also works with streaming responses:
- Python
- TypeScript
import requests
import json
url = "https://api.knox.chat/v1/chat/completions"
headers = {
"Authorization": f"Bearer {API_KEY_REF}",
"Content-Type": "application/json"
}
payload = {
"model": "google/gemini-2.5-flash-image",
"messages": [
{
"role": "user",
"content": "Create an image of a futuristic city"
}
],
"modalities": ["image", "text"],
"stream": True
}
response = requests.post(url, headers=headers, json=payload, stream=True)
for line in response.iter_lines():
if line:
line = line.decode('utf-8')
if line.startswith('data: '):
data = line[6:]
if data != '[DONE]':
try:
chunk = json.loads(data)
if chunk.get("choices"):
delta = chunk["choices"][0].get("delta", {})
if delta.get("images"):
for image in delta["images"]:
print(f"Generated image: {image['image_url']['url'][:50]}...")
except json.JSONDecodeError:
continue
const response = await fetch('https://api.knox.chat/v1/chat/completions', {
method: 'POST',
headers: {
Authorization: `Bearer ${API_KEY_REF}`,
'Content-Type': 'application/json',
},
body: JSON.stringify({
model: '{{MODEL}}',
messages: [
{
role: 'user',
content: 'Create an image of a futuristic city',
},
],
modalities: ['image', 'text'],
stream: true,
}),
});
const reader = response.body?.getReader();
const decoder = new TextDecoder();
while (true) {
const { done, value } = await reader.read();
if (done) break;
const chunk = decoder.decode(value);
const lines = chunk.split('\n');
for (const line of lines) {
if (line.startsWith('data: ')) {
const data = line.slice(6);
if (data !== '[DONE]') {
try {
const parsed = JSON.parse(data);
if (parsed.choices) {
const delta = parsed.choices[0].delta;
if (delta?.images) {
delta.images.forEach((image, index) => {
console.log(`Generated image ${index + 1}: ${image.image_url.url.substring(0, 50)}...`);
});
}
}
} catch (e) {
// Skip invalid JSON
}
}
}
}
}
Response Format
When generating images, the assistant message includes an images field containing the generated images:
{
"choices": [
{
"message": {
"role": "assistant",
"content": "I've generated a beautiful sunset image for you.",
"images": [
{
"type": "image_url",
"image_url": {
"url": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAA..."
}
}
]
}
}
]
}
Image Format
- Format: Images are returned as base64-encoded data URLs
- Types: Typically PNG format (
data:image/png;base64,) - Multiple Images: Some models can generate multiple images in a single response
- Size: Image dimensions vary by model capabilities
Model Compatibility
Not all models support image generation. To use this feature:
- Check Output Modalities: Ensure the model has
"image"in itsoutput_modalities - Set Modalities Parameter: Include
"modalities": ["image", "text"]in your request - Use Compatible Models: Examples include:
google/gemini-2.5-flash-imagegoogle/gemini-2.5-flash-image-previewgoogle/gemini-3-pro-image-preview- Other models with image generation capabilities
Best Practices
- Clear Prompts: Provide detailed descriptions for better image quality
- Model Selection: Choose models specifically designed for image generation
- Error Handling: Check for the
imagesfield in responses before processing - Rate Limits: Image generation may have different rate limits than text generation
- Storage: Consider how you'll handle and store the base64 image data
Troubleshooting
No images in response?
- Verify the model supports image generation (
output_modalitiesincludes"image") - Ensure you've included
"modalities": ["image", "text"]in your request - Check that your prompt is requesting image generation
Model not found?
- Use the Models List to find available image generation models
- Filter by output modalities to see compatible models