Merge commit '9b0050e9aabe4be65c78ccf292a348f309d50ccd' as 'docs'

```
git subtree add --prefix=docs/ https://github.com/gohugoio/hugoDocs.git master --squash
```

Closes #11925

docs/content/en/functions/images/Opacity.md

@@ -0,0 +1,52 @@
+---
+title: images.Opacity
+description: Returns an image filter that changes the opacity of an image.
+categories: []
+keywords: []
+action:
+  aliases: []
+  related:
+    - functions/images/Filter
+    - methods/resource/Filter
+  returnType: images.filter
+  signatures: [images.Opacity OPACITY]
+toc: true
+---
+
+{{< new-in 0.119.0 >}}
+
+The opacity value must be in the range [0, 1]. A value of `0` produces a transparent image, and a value of `1` produces an opaque image (no transparency).
+
+## Usage
+
+Create the filter:
+
+```go-html-template
+{{ $filter := images.Opacity 0.65 }}
+```
+
+{{% include "functions/images/_common/apply-image-filter.md" %}}
+
+The `images.Opacity` filter is most useful for target formats such as PNG and WebP that support transparency. If the source image does not support transparency, combine this filter with the `images.Process` filter:
+
+```go-html-template
+{{ with resources.Get "images/original.jpg" }}
+  {{ $filters := slice
+    (images.Opacity 0.65)
+    (images.Process "png")
+  }}
+  {{ with . | images.Filter $filters }}
+    <img src="{{ .RelPermalink }}" width="{{ .Width }}" height="{{ .Height }}" alt="">
+  {{ end }}
+{{ end }}
+```
+
+## Example
+
+{{< img
+  src="images/examples/zion-national-park.jpg"
+  alt="Zion National Park"
+  filter="Opacity"
+  filterArgs="0.65"
+  example=true
+>}}