clarify what date fields do, following [[bugs/invalid_meta_date_or_updated_not_diagno...

[git.ikiwiki.info.git] / doc / ikiwiki / directive / img.mdwn

diff --git a/doc/ikiwiki/directive/img.mdwn b/doc/ikiwiki/directive/img.mdwn
index 94cc754bd8dc5152bb638ec8957337ecc724c423..a940a44b6567ef72c9f8b23a8900a1545be508d0 100644 (file)
--- a/doc/ikiwiki/directive/img.mdwn
+++ b/doc/ikiwiki/directive/img.mdwn
@@ -12,13 +12,16 @@ providing a link to a full-size version.
 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 specify only
-the width or the height, and the other value will be calculated based on
-it: "200x", "x200"
+The `size` parameter is optional, defaulting to full size.
+You can specify only the width or the height, and the other value will
+be calculated based on it: "200x", "x200".
 
-You can also pass `alt`, `title`, `class`, `align` and `id` parameters.
+If you specify both the width and height, the original image's aspect
+ratio will be preserved, even if this means making the image smaller
+than the specified size. (However, this is not done for svg images.)
+
+You can also pass `alt`, `title`, `class`, `align`, `id`, `hspace`, and
+`vspace` 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.
 
@@ -27,6 +30,9 @@ 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.
 
+The `pagenumber` parameter selects which of multiple images should be rendered;
+this is relevant mainly for GIF and PDF source images.
+
 You can also set default values that will be applied to all later images on
 the page, unless overridden. Useful when including many images on a page.
 
@@ -35,4 +41,27 @@ the page, unless overridden. Useful when including many images on a page.
        \[[!img photo2.jpg]]
        \[[!img photo3.jpg size=200x600]]
 
+## format support
+
+By default, the `img` directive only supports a few common web formats:
+
+* PNG (`.png`)
+* JPEG (`.jpg` or `.jpeg`)
+* GIF (`.gif`)
+* SVG (`.svg`)
+
+These additional formats can be enabled with the `img_allowed_formats`
+[[!iki setup]] option, but are disabled by default for better
+[[!iki security]]:
+
+* PDF (`.pdf`)
+* `everything` (accepts any file supported by ImageMagick: make sure
+  that only completely trusted users can
+  [[upload attachments|ikiwiki/pagespec/attachment]])
+
+For example, a wiki where only `admin()` users can upload attachments might
+use:
+
+    img_allowed_formats: [png, jpeg, gif, svg, pdf]
+
 [[!meta robots="noindex, follow"]]