The `icons` directory is the place to store plugin icons. When the user goes to "Dashboard -> Updates", the appropriate icon will be displayed next to the plugin name in the list of available updates. Icons are optional. If your plugin doesn't have an icon, WordPress will display a placeholder image.

Icons must be in the PNG, JPG or SVG format. Each plugin can have up to three icon files: 
 
- `$slug-128x128.png` or `$slug-128x128.jpg`
- `$slug-256x256.png` or `$slug-256x256.jpg`
- `$slug.svg`

See the [WordPress.org documentation on plugin assets](https://developer.wordpress.org/plugins/wordpress-org/plugin-assets/#plugin-icons) for more information.