Text prompt, up to 5000 characters. Chinese and English are both supported.
0/5000Aspect ratio of the output image. auto: the prompt rewriter picks a suitable ratio (falls back to 1:1 when prompt expansion is off).
Output size tier: 1K (about 1 MP), 2K (about 4 MP, default), 4K (about 16 MP). Billed per image by this tier. Hidden and not sent when both Width and Height are set.
Optional custom output width in pixels (1–8192). Width and Height must be set together: filling one makes the other required. With both set, Aspect Ratio and Resolution are hidden and not sent (they cannot be combined with a custom size); the output is exactly Width × Height, billed by its total pixels (≤1.2 MP 1K, ≤4.5 MP 2K, otherwise 4K). Total pixels 655,360–20,000,000, width : height 1:3–3:1.
Optional custom output height in pixels (1–8192). Must be set together with Width: filling one makes the other required.
Rewrite the prompt into a detailed English description before generating. Prompt expansion is on by default; we recommend keeping it on for better image quality.
Output image format.
Random seed, 0–2147483647. Leave empty for a random seed; the actual seed is returned with the result.

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Click to upload or drag and drop
Supported formats: JPEG, PNG, WEBP, BMP Maximum file size: 20MB; Maximum files: 16
Reference images, 1–16, each up to 20 MB and 64 MP. The order defines <Picture 1>, <Picture 2>, ... in the prompt.
Editing instruction, up to 5000 characters. Refer to reference images as <Picture 1>, <Picture 2>, ... in upload order.
0/5000Aspect ratio of the output image. auto: matches the aspect ratio of the first reference image (limited to 1:3–3:1).
Output size tier: 1K (about 1 MP), 2K (about 4 MP, default), 4K (about 16 MP). Billed per image by this tier. Hidden and not sent when both Width and Height are set.
Optional custom output width in pixels (1–8192). Width and Height must be set together: filling one makes the other required. With both set, Aspect Ratio and Resolution are hidden and not sent (they cannot be combined with a custom size); the output is exactly Width × Height, billed by its total pixels (≤1.2 MP 1K, ≤4.5 MP 2K, otherwise 4K). Total pixels 655,360–20,000,000, width : height 1:3–3:1.
Optional custom output height in pixels (1–8192). Must be set together with Width: filling one makes the other required.
Rewrite the prompt into a detailed English description before generating. Prompt expansion is on by default; we recommend keeping it on for better image quality.
Output image format.
Random seed, 0–2147483647. Leave empty for a random seed; the actual seed is returned with the result.

Explore different use cases and parameter configurations
README
Complete guide to using MiniMax H3 Image
MiniMax H3 Image API for 16-Megapixel Generation and Editing

Key Capabilities of MiniMax H3 Image

Ten Aspect Ratios in Three Size Tiers

Editing With Up to 16 Reference Images

Six-Step Sampling

Text Rendering With Reasoning

Prompts in Chinese or English
MiniMax H3 Image Parameters
Model specifications for MiniMax H3 Image.
| Parameter | MiniMax H3 Image |
|---|---|
| Developer | MiniMax |
| Tasks | Text to image and image editing; one PNG or JPEG image per task |
| Output size | 1K, 2K (default) or 4K (about 1, 4 or 16 megapixels); or width and height together: up to 8,192 pixels per side, 655,360 to 20,000,000 pixels in total, and a width-to-height ratio between 1:3 and 3:1 |
| Aspect ratios | auto, 1:1, 5:4, 4:5, 4:3, 3:4, 3:2, 2:3, 16:9, 9:16, 21:9 |
| Reference images | 1 to 16 per edit, numbered in image_urls order; each up to 20 MB and 64 MP |
| Sampling | 6 steps, fixed; no classifier-free guidance |
| Negative prompt | Not supported |
| Prompt | 1 to 5,000 characters, Chinese or English; rewritten into a detailed English description by default |
| Architecture | Single-stream diffusion transformer, 33.1B parameters, 50 layers |
| Text encoder | Qwen3-VL text encoder of MiniMax H3 |
| License | MiniMax-H3-Image Community License |
MiniMax H3 Image Output Sizes at 16 Megapixels
4K output sizes on Kie.ai (about 16 megapixels); 5:4 and 4:5 are 4576×3648 and 3648×4576.
| Aspect ratio | Size (width × height) |
|---|---|
| 1:1 | 4096×4096 |
| 4:3 | 4736×3552 |
| 3:4 | 3552×4736 |
| 3:2 | 5024×3360 |
| 2:3 | 3360×5024 |
| 16:9 | 5472×3072 |
| 9:16 | 3072×5472 |
| 21:9 | 6272×2688 |
How to Prompt MiniMax H3 Image
- 1
Step 1: Describe the Whole Image
Describe the full frame: subject, setting, lighting, style and any text that should appear in the image. By default the prompt is rewritten into a detailed English description. - 2
Step 2: Pick a Size for Your Aspect Ratio
The default tier is 2K. Set resolution to 4K for about 16 megapixels, for example 4096×4096 at 1:1 or 5472×3072 at 16:9, or pass width and height together for an exact size within the limits in the specifications table above. - 3
Step 3: Add Reference Images for Edits
For an edit, use minimax-h3/image-edit with 1 to 16 reference images and refer to each one by its position in image_urls, for example <Picture 1> for the product and <Picture 2> for the style. - 4
Step 4: Iterate on the Prompt
Sampling is fixed at six steps with no classifier-free guidance, and there is no negative prompt, so changes come from rewriting the description or swapping the references. Only if you need a reproducible result, turn expand_prompt off and reuse the seed.