## Quick Start

1. Click on the selection panel to select images, or drag and drop images/folders into it 
2. Adjust the image compression options 
3. Press **Compress** to start 
4. View compression results and open files in Finder

## Compression Options

### Image Quality

| Quality | Description | Best For |
| --- | --- | --- |
| **Highest** | Maximum quality, minimal compression | Archiving, print |
| **High** | Excellent quality | Professional use |
| **Good** | Good balance of quality and size | Web images |
| **Medium** | Moderate compression | Social media |
| **Acceptable** | Higher compression, smaller files | Thumbnails, previews |

### Image Size

Resize images during compression:

| Option | Description |
| --- | --- |
| **Same as input** | Keep original dimensions (default) |
| **Percentage** | Scale by percentage (e.g., 50% = half size) |
| **Max width** | Set maximum width in pixels |
| **Max height** | Set maximum height in pixels |
| **Max long edge** | Limit the longer dimension |
| **Max short edge** | Limit the shorter dimension |

When resizing, aspect ratio is always preserved.

### Image Format

| Format | Description | Best For |
| --- | --- | --- |
| **Same as input** | Keep original format (default) | General use |
| **JPG** | Lossy compression, small files | Photos |
| **PNG** | Lossless, supports transparency | Graphics, screenshots |
| **WebP** | Modern format, excellent compression | Web images |
| **AVIF** | Newest format, best compression | Modern browsers |

## Supported Input Formats

Compresto supports compressing these image formats:

- JPG / JPEG
- PNG
- WebP
- AVIF
- HEIC
- TIFF
- BMP
- GIF (static)

## Tips for Best Results

- **For photos**: Use JPG format with “Good” or “High” quality
- **For graphics with transparency**: Use PNG or WebP format
- **For web optimization**: Use WebP format with “Good” quality
- **For maximum compression**: Use AVIF format (check browser support)
- **For batch resizing**: Use “Max long edge” to uniformly resize images