Pictures are priced by the picture

auth.pricing takes per_image, charged on top of a prompt's tokens; a model
priced only per picture is not free, so a spent budget still stops it.
Each usage row keeps how many pictures were made (migration 0041), and
ctl request and the admin API's request view show them.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/reference.md

@@ -347,6 +347,7 @@ rather than repeated.
 | `secret_file` | `string` | [Webhook](#webhook) |
 | `prompt_per_1k` | `int64` | [accounting.Price](#accountingprice) |
 | `completion_per_1k` | `int64` | [accounting.Price](#accountingprice) |
+| `per_image` | `int64` | [accounting.Price](#accountingprice) |
 | `name` | `string` | [admission.Band](#admissionband) |
 | `priority` | `int` | [admission.Band](#admissionband) |
 | `saturation_ceiling` | `float64` | [admission.Band](#admissionband) |
@@ -381,6 +382,7 @@ rather than repeated.
 | `saturation_ceiling` | `float64` | [config.Band](#configband) |
 | `prompt_per_1k` | `int64` | [config.Price](#configprice) |
 | `completion_per_1k` | `int64` | [config.Price](#configprice) |
+| `per_image` | `int64` | [config.Price](#configprice) |
 | `disabled` | `[]string` | [engines.Config](#enginesconfig) |
 | `vllm` | `VLLMConfig` | [engines.Config](#enginesconfig) |
 | `sglang` | `SGLangConfig` | [engines.Config](#enginesconfig) |
@@ -2936,6 +2938,14 @@ is sha256=<hex HMAC of the body>.
 
 `int64`
 
+### `per_image`
+
+`int64`
+
+PerImage is what one picture costs, for a model that makes them: a
+picture's cost is the card's time, which its prompt's few tokens do
+not measure.
+
 ## admission.Band
 
 ### `name`
@@ -3178,6 +3188,13 @@ Takes a [Tracing](#tracing) block.
 
 `int64`
 
+### `per_image`
+
+`int64`
+
+PerImage is the cost of one picture, for a model that makes them
+(/v1/images/generations), on top of its prompt's tokens.
+
 ## engines.Config
 
 ### `disabled`