Aspect Ratio Parameters
The proportional relationship between image width and height. Different ratios suit different uses, and AI models may perform better at certain ratios.
Aspect ratio significantly affects composition and how well AI models perform.
Common Aspect Ratios
| Ratio | Dimensions | Use Case |
|---|---|---|
| 1:1 | 1024x1024 | Instagram, avatars |
| 4:3 | 1024x768 | Traditional photo |
| 3:2 | 1024x683 | DSLR photos |
| 16:9 | 1024x576 | Video, widescreen |
| 9:16 | 576x1024 | Mobile, stories |
| 2:3 | 683x1024 | Portraits |
| 21:9 | 1024x439 | Ultrawide, cinematic |
Model Considerations
SD 1.5
- Trained on 512x512
- Works at other ratios but may distort
- Keep total pixels similar (512x768, 768x512)
SDXL
- Trained on 1024x1024
- Better at varying ratios
- Multiple aspect ratios in training
Midjourney
- Use —ar flag (e.g., —ar 16:9)
- Very flexible with ratios
- Automatic composition adjustment
Best Practices
Match Your Subject
- Portraits: Vertical (2:3, 9:16)
- Landscapes: Horizontal (16:9, 3:2)
- Products: Square (1:1)
Consider Output Use
- Social media platforms have preferences
- Print sizes have standard ratios
- Video requires 16:9 or similar
Composition Impact
- Different ratios create different feelings
- Wide = epic, expansive
- Square = balanced, focused
- Tall = dramatic, imposing
Changing Ratios
- Generate in target ratio when possible
- Outpainting can change ratio after
- Cropping loses content
- AI regeneration may help