# Image Parameters

This page documents the query parameters `GET /c/img/*path` accepts, their defaults, and normalization rules.

## Parameters

Each parameter has a short and a long name; `utils.GetQuery` takes the first non-empty one:

| Short | Long | Default | Description |
|---|---|---|---|
| `o` | `origin` | `0` | `1` returns the original file and ignores all transform parameters |
| `s` | `size` | — | Short-edge length (px); takes precedence over `w` / `h` |
| `w` | `width` | — | Width (px) |
| `h` | `height` | — | Height (px) |
| `q` | `quality` | `75` (`50` for AVIF) | Output quality, clamped to 0–100 |
| `t` | `type` | `webp` | Output format |
| `b` | `blur` | `0` | Gaussian blur sigma, clamped to 0–100 |
| `B` | `bright` | `1` | Brightness multiplier |
| `d` | `dark` | — | `1` or `dark` switches error responses to the dark placeholder |

`b` and `B` are case-sensitive: blur and brightness respectively.

## Format and Quality

| `t` value | Output | Content-Type | Quality |
|---|---|---|---|
| `webp`, empty, invalid | WebP | `image/webp` | `q`, default 75 |
| `jpg`, `jpeg` | JPEG (`jpeg` normalized to `jpg`) | `image/jpeg` | `q`, default 75 |
| `avif` | AVIF | `image/avif` | `q`, default 50 |
| `png` | PNG | `image/png` | Not applied |

Unparseable `q` and `b` fall back to their defaults; an unparseable `B` fails the transform and returns the placeholder.

## Examples

```bash
# Short edge 480 px, AVIF, quality 60
curl -o a.avif "http://localhost:8080/c/img/blog/photo.jpg?s=480&t=avif&q=60"

# Width 800 px, blur 10, brightness 0.8, dark placeholder on failure
curl -o b.webp "http://localhost:8080/c/img/blog/photo.jpg?width=800&blur=10&bright=0.8&dark=1"

# Original file
curl -o c.jpg "http://localhost:8080/c/img/blog/photo.jpg?o=1"
```

See [Sizing Rules](/api-reference-sizing) for how size parameters map to output dimensions and [Image Pipeline](/image-pipeline) for processing order.