# File formats

Choose the right format for your use case

## Supported Formats

The API supports four output formats:

*   PNG (default)
*   JPG
*   WebP
*   PDF

To specify a format, add the appropriate file extension to your image URL:

| Format | Example URL | Best For |
| --- | --- | --- |
| PNG | `https://hcti.io/v1/image/abc123.png` | Screenshots, images with transparency |
| JPG | `https://hcti.io/v1/image/abc123.jpg` | Photos, complex images with no transparency |
| WebP | `https://hcti.io/v1/image/abc123.webp` | Modern web applications, optimal compression |
| PDF | `https://hcti.io/v1/image/abc123.pdf` | Documents, invoices, printable content |

Choose a format when creating an image

Use the [`format` parameter](/parameters/format/) to select the format in your create request.

Default format

PNG is the default format. Paid accounts may receive an optimized WebP response based on the client’s capabilities, as described below.

## Format Characteristics

### PNG

*   Lossless compression
*   Supports transparency
*   Larger file size
*   Best for:
    *   Screenshots
    *   Images with text
    *   Graphics with sharp edges
    *   Content requiring transparency

### JPG

*   Lossy compression
*   No transparency support
*   Smaller file size
*   Best for:
    *   Photographs
    *   Complex images
    *   When transparency isn’t needed
    *   When smaller file size is priority

### WebP

*   Modern format
*   Supports transparency
*   Superior compression
*   Best for:
    *   Web applications
    *   Progressive loading
    *   Optimal performance
    *   Modern browsers

### PDF

*   Document format
*   Vector-based rendering
*   Ideal for printing
*   Best for:
    *   Invoices and receipts
    *   Certificates
    *   Reports
    *   Printable documents
*   Use the `pdf_options` parameter for customization ([Learn more](/parameters/pdf_options/))

## Automatic WebP Optimization

All paid accounts receive automatic WebP optimization:

1.  Our edge servers detect the user’s browser capabilities
2.  If WebP is supported, images are automatically served in WebP format
3.  Fallback formats are served for non-supporting browsers

Benefits:

*   Improved page load times
*   Better SEO scores
*   Reduced bandwidth usage
*   No code changes required

Compare the output

Compare file sizes and image quality using your actual content; compression savings vary by image.

## Best Practices

### Format Selection

1.  **Default to PNG** for:
    
    *   Screenshots
    *   Text-heavy images
    *   When quality is critical
2.  **Use JPG** for:
    
    *   Photos
    *   Complex images
    *   When file size is priority
3.  **Enable WebP** for:
    
    *   Modern web applications
    *   Performance optimization
    *   Progressive enhancement

## Browser Support

| Format | Chrome | Firefox | Safari | Edge | IE11 |
| --- | --- | --- | --- | --- | --- |
| PNG | ✅ | ✅ | ✅ | ✅ | ✅ |
| JPG | ✅ | ✅ | ✅ | ✅ | ✅ |
| WebP | ✅ | ✅ | ✅ | ✅ | ❌ |
| PDF | ✅ | ✅ | ✅ | ✅ | ✅ |

## Need help?

Talk to a human. Email [support@htmlcsstoimage.com](mailto:support@htmlcsstoimage.com) and we’ll help you get started.