-The `alt` parameter is optional. The `size` parameter is also optional,
-defaulting to full size. Note that the original image's aspect ratio is
-always preserved, even if this means making the image smaller than the
-specified size.
+The image file will be searched for using the same rules as used to find
+the file pointed to by a [[ikiwiki/WikiLink]].
+
+The `size` parameter is optional, defaulting to full size. Note that the
+original image's aspect ratio is always preserved, even if this means
+making the image smaller than the specified size.
+
+You can also pass `alt`, `title`, `class` and `id` parameters. These are
+passed through unchanged to the html img tag. If you include a `caption`
+parameter, the caption will be displayed centered beneath the image.
+
+The `link` parameter is used to control whether the scaled down image links
+to the full size version. By default it does; set "link=somepage" to link
+to another page instead, or "link=no" to disable the link, or
+"link=http://url" to link to a given url.