Help:Images: Difference between revisions
(Created page with "This page explains the '''image''' syntax when editing the wiki. You or another user must usually upload an image before you can use it on a page. Ima...") |
No edit summary |
||
Line 1: | Line 1: | ||
This page explains the '''image''' syntax when editing the wiki. You or another user must usually [[ | This page explains the '''image''' syntax when editing the wiki. You or another user must usually [[Special:Upload]] before you can use it on a page. | ||
Images that are stored on a MediaWiki server are usually rendered by using the <code>File:</code> namespace prefix (but the legacy <code>Image:</code> namespace prefix is still supported as a synonym) as the target of a MediaWiki link. The alternate <code>Media:</code> namespace prefix is also usable to reference the original media file content (for rendering or downloading it separately, out of any MediaWiki page). | Images that are stored on a MediaWiki server are usually rendered by using the <code>File:</code> namespace prefix (but the legacy <code>Image:</code> namespace prefix is still supported as a synonym) as the target of a MediaWiki link. The alternate <code>Media:</code> namespace prefix is also usable to reference the original media file content (for rendering or downloading it separately, out of any MediaWiki page). | ||
Line 41: | Line 41: | ||
* ''[[#Altering the default link target|Link]] option'': one of | * ''[[#Altering the default link target|Link]] option'': one of | ||
** '''link='''''{target}'' — Allows to change the target (to an arbitrary page title, or URL) of the generated link, activable on the rendered image surface; e.g. <code><nowiki>[[File:Example.jpg|20px|link=http://www.wikipedia.org]]</nowiki></code> renders as [[File:Example.jpg|20px|link=http://www.wikipedia.org]] (external link), or <code><nowiki>[[File:Example.jpg|20px|link=MediaWiki]]</nowiki></code> renders as [[File:Example.jpg|20px|link=MediaWiki]] (internal link). | ** '''link='''''{target}'' — Allows to change the target (to an arbitrary page title, or URL) of the generated link, activable on the rendered image surface; e.g. <code><nowiki>[[File:Example.jpg|20px|link=http://www.wikipedia.org]]</nowiki></code> renders as [[File:Example.jpg|20px|link=http://www.wikipedia.org]] (external link), or <code><nowiki>[[File:Example.jpg|20px|link=MediaWiki]]</nowiki></code> renders as [[File:Example.jpg|20px|link=MediaWiki]] (internal link). | ||
** '''link=''' (with an empty value) — | ** '''link=''' (with an empty value) — Displays an image without any activable link; e.g. <code><nowiki>[[</nowiki>File:Example.jpg|20px|link=]]</code> renders as [[File:Example.jpg|20px|link=]]. | ||
*** '''!''' Link does '''not''' work with thumb, thumbnail or frame. | *** '''!''' Link does '''not''' work with thumb, thumbnail or frame. | ||
*** '''!''' If you set <code>|link=|</code> (empty), then no <code>title</code> will be rendered. (see [[bugzilla:21454]]) | *** '''!''' If you set <code>|link=|</code> (empty), then no <code>title</code> will be rendered. (see [[bugzilla:21454]]) | ||
* Other specific options: | * Other specific options: | ||
** '''alt='''''{alternative text}'' — | ** '''alt='''''{alternative text}'' — Defines the alternative text (maps to the HTML attribute <code>alt="..."</code> of the generated <code><image /></code> element) of an image that will be rendered if either the referenced image cannot be downloaded and embedded, or if the support media must use the alternative description text (e.g. when using a Braille reader or with accessibility options set by the user in its browser). | ||
** '''page='''''{number}'' — Renders the specified page number (currently only applicable when showing a .djvu or .pdf file). | ** '''page='''''{number}'' — Renders the specified page number (currently only applicable when showing a .djvu or .pdf file). | ||
Line 111: | Line 111: | ||
Note that the rendered line of text where inline images are inserted (and the lines of text rendered after the current one) may be moved down (this will increase the line-height conditionally by additional line spacing, just as it may occur with spans of text with variable font sizes, or with superscripts and subscripts) to allow the image height to be fully displayed with this alignment constraint. | Note that the rendered line of text where inline images are inserted (and the lines of text rendered after the current one) may be moved down (this will increase the line-height conditionally by additional line spacing, just as it may occur with spans of text with variable font sizes, or with superscripts and subscripts) to allow the image height to be fully displayed with this alignment constraint. | ||
<div class="mw-collapsible mw-collapsed"><div class="mw-collapsible-toggle toccolours" style="float:none;text-align:center"> | <div class="mw-collapsible mw-collapsed"><div class="mw-collapsible-toggle toccolours" style="float:none;text-align:center"></div> | ||
<div class="mw-collapsible-content"> | <div class="mw-collapsible-content"> | ||
<source lang="html4strict" enclose="div"> | <source lang="html4strict" enclose="div"> | ||
Line 318: | Line 318: | ||
== Linking to an image without displaying it == | == Linking to an image without displaying it == | ||
=== Link to another page === | === Link to another page === | ||
This will make a 50px width picture with a link to the page [[MediaWiki]]: | This will make a 50px width picture with a link to the page [[MediaWiki]]: | ||
Line 361: | Line 349: | ||
which generates an external URL to the file inline: {{FILEPATH:{{mediawiki:image_sample}}}} | which generates an external URL to the file inline: {{FILEPATH:{{mediawiki:image_sample}}}} | ||
== Files at other websites == | == Files at other websites == | ||
Line 375: | Line 360: | ||
<pre>[http://www.example.com/some/image.png Example '''<del>rich</del>''' ''<ins>link text</ins>'' here.]</pre> | <pre>[http://www.example.com/some/image.png Example '''<del>rich</del>''' ''<ins>link text</ins>'' here.]</pre> | ||
which renders as: [http://www.example.com/some/image.png Example '''<del>rich</del>''' ''<ins>link text<ins>'' here.] | which renders as: [http://www.example.com/some/image.png Example '''<del>rich</del>''' ''<ins>link text<ins>'' here.] | ||
[[Category:Help|Images]] | [[Category:Help|Images]] |
Revision as of 03:38, 2 July 2012
This page explains the image syntax when editing the wiki. You or another user must usually Special:Upload before you can use it on a page.
Images that are stored on a MediaWiki server are usually rendered by using the File:
namespace prefix (but the legacy Image:
namespace prefix is still supported as a synonym) as the target of a MediaWiki link. The alternate Media:
namespace prefix is also usable to reference the original media file content (for rendering or downloading it separately, out of any MediaWiki page).
Supported media types for images
The following file formats are supported by default:
- .jpg or .jpeg : bitmap image compressed in the standard JPEG format (this lossy format is most suitable for photographs).
- .png : bitmap image in the Portable Network Graphics format (specified by the W3 Consortium).
- .gif : bitmap image in the legacy Graphics Interchange Format.
Other formats used on Wikimedia, and commonly enabled elsewhere (these may require extra set-up beyond what is enabled by default):
- .svg : scalable image in the Scalable Vector Graphics format (specified by the W3 Consortium).
- .tiff : Tagged image format. Often used for high-resolution archival photographs. <-- Often used with Template:Mediawiki. -->
- .ogg, .oga, .ogv : Ogg multimedia (audio or video) Not an image format, but treated similarly. <-- Often used with Template:Mediawiki -->
- .pdf : multipaged documents in the Portable Document Format (initially specified by Adobe). <-- Often used in conjunction with Template:Mediawiki -->
- .djvu : multipaged bitmap documents in the DejaVu format (most often, scans of books). <-- See Template:Mediawiki -->
- Only a single page of a .pdf or .djvu file is shown at one time.
Other media types may be supported, but it may not be possible to display them inline.
Rendering a single image
Syntax
The full syntax for displaying an image is:
[[File:filename.extension|options|caption]]
where options can be zero or more of the following, separated by pipes (|):
- Format option: one of border and/or frameless, frame, thumb (or thumbnail);
- Controls how the rendered image is formatted and embedded in the rest of the page.
- Resizing option: one of
- {width}px — Resizes the image to fit within the given maximum width in pixels, without restricting its height;
- x{height}px — Resizes the image to fit within the given maximum height in pixels, without restricting its width;
- {width}x{height}px — Resizes the image to fit within the given width and height in pixels;
- upright — Resizes an image to fit within reasonable dimensions, according to user preferences (suitable for images whose height is larger than width).
- Note that the image will always retain its aspect ratio, and can only be reduced (not increased) in size unless it's in a scalable media type (bitmap images cannot be scaled up).
- The default maximum size depends on the format and the internal image dimensions (according to its media type).
- Horizontal alignment option: one of left, right, center, none;
- Controls the horizontal alignment (and inline/block or floating styles) of the image within a text (no default value).
- Vertical alignment option: one of baseline, sub, super, top, text-top, middle, bottom, text-bottom;
- Controls the vertical alignment of a non-floating inline image with the text before or after the image, and in the same block (the default vertical alignment is middle).
- Link option: one of
- link={target} — Allows to change the target (to an arbitrary page title, or URL) of the generated link, activable on the rendered image surface; e.g.
[[File:Example.jpg|20px|link=http://www.wikipedia.org]]
renders as (external link), or[[File:Example.jpg|20px|link=MediaWiki]]
renders as (internal link). - link= (with an empty value) — Displays an image without any activable link; e.g.
[[File:Example.jpg|20px|link=]]
renders as .- ! Link does not work with thumb, thumbnail or frame.
- ! If you set
|link=|
(empty), then notitle
will be rendered. (see bugzilla:21454)
- link={target} — Allows to change the target (to an arbitrary page title, or URL) of the generated link, activable on the rendered image surface; e.g.
- Other specific options:
- alt={alternative text} — Defines the alternative text (maps to the HTML attribute
alt="..."
of the generated<image />
element) of an image that will be rendered if either the referenced image cannot be downloaded and embedded, or if the support media must use the alternative description text (e.g. when using a Braille reader or with accessibility options set by the user in its browser). - page={number} — Renders the specified page number (currently only applicable when showing a .djvu or .pdf file).
- alt={alternative text} — Defines the alternative text (maps to the HTML attribute
The options can be given in any order. If the given options conflict each other, the latter is applied, except for the format options, where the options take the priority in the order of: frame; thumb (or thumbnail); frameless and/or border.
If a parameter does not match any of the other possibilities, it is assumed to be the caption text. Caption text shows below the image in thumb and frame formats, or as mouseover text in border, frameless formats or when the format is omitted. Caption text displayed in the thumb and frame formats may contain wiki links and other formatting. In the other options, wiki-formatting will not work though transclusion will.
If no caption text is supplied, a caption is automatically created showing the file name. To completely remove the caption, set it to <span title=""></span>
. For example, [[File:Example.jpg|20px|<span title=""></span>]]
renders as .
Format
The following table shows the effect of all available formats.
Description | You type | You get
Help:Images/frame Help:Images/frame Help:Images/frame Help:Images/frame Help:Images/frame Help:Images/frame |
---|
When the height of an image in thumbnail is bigger than its width (i.e. in portrait orientation rather than landscape) and you find it too large, you may try the option upright
, which will try to adjust its size to a more desirable size by reducing the height instead of the width. The alternative is to specify the desired maximum height (in pixels) explicitly.
Note that by writing thumb={filename}
, you can use a different image for the thumbnail.
Size and frame
Among different formats, the effect of the size parameter may be different, as shown below.
- For how it appears when its size is not specified, see Format section above.
- When the format is not specified, or only
border
ed, the size can be both reduced and enlarged to any specified size. - In the examples below, the original size of the image is 400 × 267 pixels.
- An image with
frame
always ignores the size specification, the original image will be reduced if it exceeds the maximum size defined in user preferences. - The size of an image with
thumb
can be reduced, but can not be enlarged beyond the original size of the image.
Format | Reduced | Enlarged
Help:Images/size Help:Images/size Help:Images/size Help:Images/size Help:Images/size |
---|
Horizontal alignment
Note that when using the frame
or thumb[nail]
formats, the default horizontal alignment will be right
.
Description | You type | You get
Help:Images/frame Help:Images/frame Help:Images/frame Help:Images/frame Help:Images/frame |
---|
Vertical alignment
The vertical alignment options take effect only if the image is rendered as an inline element and is not floating. They alter the way the inlined image will be vertically aligned with the text present in the same block before and/or after this image on the same rendered row.
Note that the rendered line of text where inline images are inserted (and the lines of text rendered after the current one) may be moved down (this will increase the line-height conditionally by additional line spacing, just as it may occur with spans of text with variable font sizes, or with superscripts and subscripts) to allow the image height to be fully displayed with this alignment constraint.
To show the alignment result more clearly, the text spans are overlined and underlined, the line-height is increased to 200% of the font-height, the font-height is emphasized with a yellow background covering the line margins, and the full line-height is shown with a dark gray border; additionally images of different sizes are aligned, including one with an additional border that adds some pixels to its specified dimensions and slightly changes its vertical alignment:
Notes:
- The "middle" vertical alignment position of the image (which is also the default) usually refers to the middle between the x-height and the baseline of the text (on which the vertical middle of the image will be aligned, and on which usually the text may be overstroke), but not to the middle of the line-height of the font-height that refers to the space between the "text-top" and "text-bottom" positions ; the font-height excludes:
- the additional line separation spacing normally divided equally into two line-margins (here 0.5em, according to line-height set to 200%) above and below the font-height).
- the additional line spacing which may be added by superscripts and subscripts.
- However, if the image height causes its top or bottom position to go above or below the normal full line-height of text, the middle position will be adjusted after the increasing the top and/or bottom line-margins so that the image can fit and align properly, and all images (including those with smaller heights) will be vertically centered on the adjusted middle position (for computing the effective line-height, the text of each rendered row with the larger font-height will be considered).
- The "text-top" and "text-bottom" alignment positions also excludes the extra line spacing added by superscripts and subscripts, but not the additional line-spacing defined by the line-height.
- The "top" and "bottom" alignment positions take into account all these extra line spacings (including superscripts and subscripts, if they are present in a rendered line span). When the image alignment constrains the image to grow above or below the normal line-spacing, and the image is not absolutely positioned, the image will cause the "top" and "bottom" positions to be adjusted (just like superscripts and subscripts), so the effective line-height between rendered lines of text will be higher.
- The "underline", "overline" and "overstrike" text-decoration positions should be somewhere within these two limits and may depend on the type and height of fonts used (the superscript and subscript styles may be taken into account in some browsers, but usually these styles are ignored and the position of these decorations may not be adjusted); so these decorations normally don't affect the vertical position of images, relatively to the text.
Stopping the text flow
On occasion it is desirable to stop text (or other inline non-floating images) from flowing around a floating image. Depending on the web browser's screen resolution and such, text flow on the right side of an image may cause a section header (for instance, == My Header ==) to appear to the right of the image, instead of below it, as a user may expect. The text flow can be stopped by placing <br style="clear: both" /> before the text that should start below the floating image.
All images rendered as blocks (including non-floating centered images, left- or right-floating images, as well as framed or thumbnailed floating images) are implicitly breaking the surrounding lines of text (terminating the current block of text before the image, and creating a new paragraph for the text after them). They will then stack vertically along their left or right alignment margin (or along the center line between these margins for centered images).
Altering the default link target
The following table shows how to alter the link target (whose default is the image description page) or how to remove it. Changing the link does not alter the format described in the previous sections.
Description | You type | You get |
---|
Warning:
- The licencing requirements on your wiki may not allow you to remove all links to the description page that displays the required authors attributions, the copyrights statements, the applicable licencing terms, or a more complete description of the rendered image (including its history of modifications).
- If you change or remove the target link of an image, you will then have to provide somewhere else on your page an explicit link to this description page, or to display the copyright and author statement and a link to the applicable licence, if they are different from the elements applicable to the embedding page itself.
- Your wiki policy may restrict the use of the alternate link parameter, or may even enforce a prohibition of alternate link parameters for embedded media files (in which case, the link parameter will be ignored), or may only accept them after validation by authorized users or administrators.
Rendering a gallery of images
Gallery syntax
It's easy to make a gallery of thumbnails with the <gallery>
tag. The syntax is:
<gallery> Image:file_name.ext|caption Image:file_name.ext|caption {...} </gallery>
Note that the image code is not enclosed in brackets when enclosed in gallery tags.
Captions are optional, and may contain wiki links or other formatting.
for example:
<gallery> File:Example.jpg|Item 1 File:Example.jpg|a link to [[Help:Contents]] File:Example.jpg File:Example.jpg File:Example.jpg| ''italic caption'' File:Example.jpg|on page "{{PAGENAME}}" </gallery>
is formatted as:
a link to Help:Contents
Optional gallery attributes
The gallery tag itself takes several additional parameters, specified as attribute name-value pairs:
<gallery {parameters}> {images} </gallery>
caption="{caption}"
: (caption in parentheses for more than a word) sets a caption centered atop the gallery.widths={width}px
: sets the widths of the images, default 120px. Note the plural, widthsheights={heights}px
: sets the (max) heights of the images.perrow={integer}
: sets the number of images per row.showfilename={anything}
: Show the filenames of the images in the individual captions for each image (1.17+)
Example:
Coding:
<gallery widths=60px heights=60px perrow=7 caption="sunflowers are groovy"> File:Example.jpg File:Example.jpg File:Example.jpg File:Example.jpg File:Example.jpg File:Example.jpg File:Example.jpg File:Example.jpg File:Example.jpg File:Example.jpg </gallery>
Result:
Linking to an image without displaying it
Link to another page
This will make a 50px width picture with a link to the page MediaWiki:
[[File:Wiki.png|50px|link=MediaWiki]]
Link directly to the media file
You can use the pseudo-namespace “Media” to link directly to a file without rendering it, bypassing the description page.
[[Media:MediaWiki:Image sample]] [[Media:MediaWiki:Image sample|Sunflowers]]
results in
[[Media:MediaWiki:Image sample]] [[Media:MediaWiki:Image sample|Sunflowers]]
The same result can be achieved by adding a colon before the namespace (works with categories too):
[[:File:MediaWiki:Image sample]]
You can also use:
[[Special:FilePath/MediaWiki:Image sample]]
which can be used to link to a potential file, even if it doesn't exist. You can also use:
{{FILEPATH:MediaWiki:Image sample}}
which generates an external URL to the file inline:
Files at other websites
You can link to an external file available online using the same syntax used for linking to an external web page. With these syntaxes, the image will not be rendered, but only the text of the link to this image will be displayed.
[http://url.for/some/image.png]
Or with a different displayed text:
[http://url.for/some/image.png link text here]
Additional MediaWiki markup or HTML/CSS formatting (for inline elements) is permitted in this displayed text (with the exception of embedded links that would break the surrounding link):
[http://www.example.com/some/image.png Example '''<del>rich</del>''' ''<ins>link text</ins>'' here.]
which renders as: Example rich link text here.