> ## Documentation Index > Fetch the complete documentation index at: https://docs.modellix.ai/llms.txt > Use this file to discover all available pages before exploring further. # GPT Image 1.5 > [Core Function] GPT Image 1.5 is a versatile text-to-image generation model. [Strengths] It balances solid visual performance with crucial utility features, notably its native support for generating images with transparent backgrounds. [Best For] Highly recommended for: creating UI icons, standalone logos, game assets, and any graphic design elements that require a transparent background. [Limitations] Do NOT use this model if you need 2K or 4K resolution. Its maximum supported resolution is 1536x1024. [Routing] Choose this model specifically when the user asks for 'transparent background', 'no background', or 'PNG icon'. For standard, high-fidelity, or 4K image generation, use GPT Image 2 instead. ## OpenAPI ````yaml /model-api/openai/openai-t2i.json post /openai/gpt-image-1.5 openapi: 3.1.0 info: description: The text-to-image models API from OpenAI. version: 1.0.0 contact: name: Modellix Support email: support@modellix.ai title: OpenAI Text-to-Image Models API servers: - url: https://api.modellix.ai/api/v1 description: The text-to-image models API from OpenAI. security: - bearerAuth: [] paths: /openai/gpt-image-1.5: post: tags: - GPT Image summary: GPT Image 1.5 description: >- [Core Function] GPT Image 1.5 is a versatile text-to-image generation model. [Strengths] It balances solid visual performance with crucial utility features, notably its native support for generating images with transparent backgrounds. [Best For] Highly recommended for: creating UI icons, standalone logos, game assets, and any graphic design elements that require a transparent background. [Limitations] Do NOT use this model if you need 2K or 4K resolution. Its maximum supported resolution is 1536x1024. [Routing] Choose this model specifically when the user asks for 'transparent background', 'no background', or 'PNG icon'. For standard, high-fidelity, or 4K image generation, use GPT Image 2 instead. operationId: gptImage15Async requestBody: description: Request payload for standard GPT Image generation models. required: true content: application/json: schema: $ref: '#/components/schemas/StandardGPTImageRequest' examples: basic: summary: Basic image generation value: prompt: A futuristic robot assistant in a modern home transparent: summary: Transparent background icon value: prompt: A minimalist logo icon of a mountain peak size: 1024x1024 background: transparent responses: '200': description: Task submitted successfully content: application/json: schema: $ref: '#/components/schemas/AsyncTaskResponse' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '429': $ref: '#/components/responses/TooManyRequests' '500': $ref: '#/components/responses/InternalServerError' components: schemas: StandardGPTImageRequest: description: Request payload for standard GPT Image generation models. type: object required: - prompt properties: prompt: type: string description: Image description text, supports up to 32,000 characters minLength: 1 maxLength: 32000 example: A serene zen garden with a stone path and bamboo size: type: string description: Image size. Preset resolutions only default: 1024x1024 enum: - 1024x1024 - 1536x1024 - 1024x1536 example: 1024x1024 quality: type: string description: >- Image quality level. 'low': fast draft (default), 'medium': balanced, 'high': best quality default: low enum: - low - medium - high example: high background: type: string description: >- Background transparency. 'transparent': transparent background (requires png or webp format), 'opaque': solid background, 'auto': model decides default: auto enum: - transparent - opaque - auto example: transparent AsyncTaskResponse: description: Response object for asynchronous task submission. type: object required: - code - message - data properties: code: type: integer description: Response code, 0 indicates success example: 0 message: type: string description: Response message example: success data: description: Detailed data about the submitted asynchronous task. type: object required: - status - task_id - model_id properties: status: type: string enum: - pending - processing description: Task status example: pending task_id: type: string description: Unique task identifier example: task-openai-abc123 model_id: type: string description: Model ID example: gpt-image-2 get_result: type: object description: API information to query the task result properties: method: type: string description: HTTP method example: GET url: type: string description: Full URL to query the task result example: https://api.modellix.ai/api/v1/tasks/task-openai-abc123 ErrorResponse: description: Standard error response object. type: object required: - code - message properties: code: type: integer description: Error code (equals HTTP status code) example: 400 message: type: string description: 'Error message in format ''Category: detail''' example: 'Invalid parameters: parameter ''prompt'' is required' responses: BadRequest: description: Invalid request parameters content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: missing_prompt: summary: Missing required parameter value: code: 400 message: 'Invalid parameters: parameter ''prompt'' is required' invalid_size: summary: Invalid size parameter value: code: 400 message: 'Invalid parameters: size must be one of the supported values' content_violation: summary: Content policy violation value: code: 400 message: 'Content policy violation: prompt contains prohibited content' Unauthorized: description: Unauthorized - Invalid or missing API Key content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: code: 401 message: 'Authentication failed: invalid API key' TooManyRequests: description: Too many requests - Rate limit exceeded or insufficient quota headers: Retry-After: description: Seconds to wait before retrying (optional) schema: type: integer example: 20 X-RateLimit-Limit-Requests: description: Maximum requests per minute schema: type: integer example: 5 X-RateLimit-Limit-Tokens: description: Maximum tokens per minute schema: type: integer example: 100000 X-RateLimit-Remaining-Requests: description: Remaining requests in current window schema: type: integer example: 0 X-RateLimit-Remaining-Tokens: description: Remaining tokens in current window schema: type: integer example: 0 X-RateLimit-Reset-Requests: description: Time when request limit resets (RFC3339 format) schema: type: string example: '2024-04-23T12:00:00Z' X-RateLimit-Reset-Tokens: description: Time when token limit resets (RFC3339 format) schema: type: string example: '2024-04-23T12:00:00Z' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: rate_limit: summary: Rate limit exceeded value: code: 429 message: 'Rate limit exceeded: too many requests, retry after 20 seconds' insufficient_quota: summary: Insufficient quota value: code: 429 message: >- Quota exceeded: insufficient quota, please check your plan and billing InternalServerError: description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: server_error: summary: Server error value: code: 500 message: 'Internal server error: please try again later' service_unavailable: summary: Service unavailable value: code: 503 message: 'Service unavailable: OpenAI service is temporarily unavailable' securitySchemes: bearerAuth: type: http scheme: bearer description: 'API Key authentication. Format: `Bearer YOUR_API_KEY`.' ````