# GPT-Image2 Prompt Template Structure: Complete JSON Specification Guide

> Explore the GPT-Image2 prompt template structure with our complete JSON specification guide. Learn how to organize image generation parameters efficiently for stunning results.

- Repository: [苍何/awesome-gpt-image-2](https://github.com/freestylefly/awesome-gpt-image-2)
- Tags: api-reference
- Published: 2026-08-29

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**A GPT-Image2 prompt template is a JSON-like hierarchical specification that organizes image generation parameters into optional top-level fields including style, structure, content, camera, scene, and category-specific blocks such as character, brand, or product.**

The `freestylefly/awesome-gpt-image-2` repository defines a standardized approach to structuring prompts for GPT-Image2. This system uses a **self-documenting JSON architecture** that separates visual requirements into logical, reusable components, enabling precise control over AI-generated imagery through modular template definitions.

## Core Components of a GPT-Image2 Prompt Template

According to the source code in [`docs/templates.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/docs/templates.md), a GPT-Image2 prompt template consists of up to eleven top-level keys that describe distinct aspects of the desired output. Each field is optional and populated only when the template's **category** requires it.

The complete field hierarchy includes:

- **`style`** – Defines color schemes, lighting moods, artistic textures, and overall visual atmosphere
- **`structure`** – Describes layout primitives including UI components, infographic modules, typography grids, or poster sections
- **`content`** – Contains placeholders for textual elements such as titles, subtitles, data points, or body copy
- **`camera`** – Specifies photographic parameters including lens type, focal length, aperture, and lighting directions
- **`scene`** – Outlines the main subject, background elements, props, and atmospheric effects like fog or glow
- **`character`** – Captures character-specific attributes including pose, expression, and costume details
- **`brand`** – Includes brand identity specifications for logo-oriented generation tasks
- **`product`** – Provides product-specific descriptors for e-commerce and catalog imagery
- **`quality_constraints`** – Enforces technical limits on resolution, aspect ratio, and prohibited elements (negative prompts)
- **`output_requirements`** – Dictates final formatting rules such as JSON output, caption annotations, or file specifications

## Template Categories and Conditional Fields

Templates are organized by **category** (UI, infographic, poster, product, brand, architecture, photo, illustration, character, scene, history, document, or other). The [`agents/skills/gpt-image-2-style-library/references/style-library.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/agents/skills/gpt-image-2-style-library/references/style-library.md) file maps each category to its required template blocks using anchor tags like `#tpl-ui` and `#tpl-poster`.

A UI template might heavily populate `structure` and `content` while omitting `character` and `camera`. Conversely, a photography template would prioritize `camera` and `scene` while leaving `brand` and `product` empty.

## Real-World Template Examples

The repository provides concrete JSON implementations demonstrating how these fields combine in practice.

### UI Design Template

This excerpt from [`docs/templates.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/docs/templates.md) demonstrates a minimal UI generation template:

```json
{
  "style": {
    "palette": "cool-blue",
    "texture": "smooth-glass"
  },
  "structure": {
    "header": {"title": "{title}", "icon": "app"},
    "sidebar": {"items": ["{item1}", "{item2}", "{item3}"]},
    "content": {"cards": [{"title": "{cardTitle}", "description": "{cardDesc}"}]}
  },
  "camera": {
    "lens": "50mm",
    "lighting": "soft-front"
  },
  "quality_constraints": {
    "aspect_ratio": "16:9",
    "max_resolution": "4k"
  }
}

```

### Marketing Poster Template

For promotional materials, the template emphasizes dramatic styling and output specifications:

```json
{
  "style": {"mood": "dramatic", "colour": "high-contrast"},
  "structure": {"headline": "{headline}", "subhead": "{subhead}", "visual": "{visual_desc}"},
  "scene": {"subject": "{subject}", "background": "{bg_desc}"},
  "output_requirements": {"format": "png", "size": "1200x1800"}
}

```

## Template Processing Workflow

As documented in [`agents/skills/gpt-image-2-style-library/SKILL.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/agents/skills/gpt-image-2-style-library/SKILL.md), the template system operates through a three-stage pipeline:

1. **Selection** – The agent identifies the appropriate template category based on user intent
2. **Hydration** – Placeholder braces (e.g., `{title}`, `{subject}`, `{cardDesc}`) are substituted with concrete values provided by the user
3. **Assembly** – The populated JSON structure is converted into the final prompt payload sent to the GPT-Image2 API

This workflow ensures that **self-documenting** templates remain reusable across different projects while maintaining strict type safety for image generation parameters.

## Source Code Reference

The implementation spans four primary files within the repository:

| File Path | Description |
|-----------|-------------|
| [`docs/templates.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/docs/templates.md) | Comprehensive collection of all template categories with full JSON examples and field definitions (lines 27–28, 110–114, 363–370, and throughout) |
| [`agents/skills/gpt-image-2-style-library/references/style-library.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/agents/skills/gpt-image-2-style-library/references/style-library.md) | Category index linking template types (`#tpl-ui`, `#tpl-poster`, etc.) to their source definitions |
| [`agents/skills/gpt-image-2-style-library/SKILL.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/agents/skills/gpt-image-2-style-library/SKILL.md) | Agent workflow documentation explaining template selection, placeholder replacement, and prompt assembly |
| [`README.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/README.md) | High-level overview of template categories with quick navigation links to specific sections |

## Summary

- **GPT-Image2 prompt templates** use a JSON-like structure with eleven optional top-level fields organizing visual, technical, and content requirements
- **Category-driven field selection** determines which blocks (UI, character, camera, etc.) are included in a specific template
- **Placeholder substitution** uses brace notation (`{variable}`) to convert static templates into dynamic prompts
- **Source documentation** resides primarily in [`docs/templates.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/docs/templates.md) with agent logic implemented in the `gpt-image-2-style-library` skill directory
- **Self-documenting design** ensures templates remain readable and maintainable without external documentation

## Frequently Asked Questions

### What are the required fields in a GPT-Image2 prompt template?

No fields are strictly required. The template structure is **flexible by design**, with each of the eleven top-level keys (style, structure, content, camera, scene, character, brand, product, quality_constraints, output_requirements) included only when relevant to the specific category. A minimal template might contain only a `style` block, while complex UI templates utilize multiple sections.

### How do I choose the right template category for my image generation?

Select the category that best matches your output domain. The [`style-library.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/style-library.md) reference file defines thirteen categories: UI, infographic, poster, product, brand, architecture, photo, illustration, character, scene, history, document, and other. Each category maps to specific template blocks—for example, choose "product" for e-commerce imagery requiring the `product` field, or "photo" for realistic photography needing detailed `camera` specifications.

### What is the difference between "style" and "structure" in GPT-Image2 templates?

**Style** defines the aesthetic qualities of the image—color palettes, lighting moods, textures, and artistic techniques. **Structure** defines the spatial organization and component layout—where elements appear, their hierarchy, and their geometric relationships. For instance, a style might specify "neon cyberpunk aesthetic" while the structure defines "header at top, sidebar on left, content grid in center."

### Where can I find the complete template reference documentation?

The definitive reference is located at [`docs/templates.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/docs/templates.md) in the repository root, which contains exhaustive JSON examples for all thirteen categories. For implementation details on how agents process these templates, consult [`agents/skills/gpt-image-2-style-library/SKILL.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/agents/skills/gpt-image-2-style-library/SKILL.md). The [`README.md`](https://github.com/freestylefly/awesome-gpt-image-2/blob/main/README.md) provides a navigational overview with quick links to specific template sections.