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Help:Images

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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.

Images that are stored on a PetroWiki server are rendered by using the File: prefix as the target of a PetroWiki 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 PetroWiki page).

Quick start

What's below describes lots of options for controlling how an image is displayed on a page. You don't have to understand all of your options to include a graphic in a page you're editing. Just do the following:

  • Upload an image and write down its name
  • With your cursor at the point where you want the image, click the image button ( ) on the edit toolbar
  • [[File:Example.jpg]] will be inserted in the page
  • Replace Example.jpg with the name of the file you uploaded (replace any spaces in the filename with underscores)
  • If the image you uploaded is large, enter |thumb between the filename and the closing double bracket ( [[File:Example.jpg|thumb]] ) to display a thumbnail of the image in the page. A reader can click on the thumbnail to display the full size file.

Take a look at the Preview to see if you need any options to change the display. You may find that's all you need to do.

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 that may be enabled include:

  • .svg : scalable image in the Scalable Vector Graphics format (specified by the W3 Consortium).
  • .tiff : Tagged image format. Should only be used for high-resolution archival photographs.
  • .ogg, .oga, .ogv : Ogg multimedia (audio or video) Not an image format, but treated similarly.
  • .pdf : multipaged documents in the Portable Document Format (initially specified by Adobe).
    Only a single page of a .pdf 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=PetroWiki]] 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 no title will be rendered.
  • 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 .pdf file).

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

no format specified Rendered as a floating block: no Rendered inline: yes

... text text text 
[[File:example.jpg|caption]]
text text text ...
... text text text

text text text ...

border results in a very small gray border Rendered as a floating block: no

Rendered inline: yes
... text text text 
[[File:example.jpg|<b>border</b>
|caption]] 
text text text ...

... text text text

text text text ...

frameless like thumbnail, respect user preferences for image width, but without border and no right float Rendered as a floating block: no

Rendered inline: yes
... text text text 
[[File:example.jpg|<b>frameless
</b>|caption]] 
text text text ...

... text text text

text text text ...

frameless and border Rendered as a floating block: no

Rendered inline: yes
... text text text 
[[File:example.jpg|<b>frameless
</b>|<b>border</b>|caption]] 
text text text ...

... text text text

text text text ...

frame Rendered as a floating block: yes

Rendered inline: no
... text text text 
[[File:example.jpg|<b>frame</b>
|caption]] 
text text text ...

... text text text   text text text ...

thumb or thumbnail Rendered as a floating block: yes

Rendered inline: no
... text text text
[[File:example.jpg|<b>thumb
</b>|caption]]
text text text ...

... text text text

text text text ...

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.

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).

Rendering a gallery of images

Gallery syntax

It's easy to make a gallery of thumbnails with the <gallery> tag. The syntax is:

<gallery>
File:file_name.ext|caption|alt=alt language
File:file_name.ext|caption|alt=alt language
{...}
</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|alt=An example image. It has flowers
File:Example.jpg| ''italic caption''
File:Example.jpg|on page "{{PAGENAME}}"
</gallery>

is formatted as:

Optional gallery attributes

The gallery tag itself takes several additional parameters, specified as attribute name-value pairs:

<gallery {parameters}>
{images}
</gallery>
  • caption="{caption}": (caption text between double quotes 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, widths
  • heights={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:

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 wiki 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.

More image formatting options

For additional options related to formatting image placement and text wrapping, see Wikipedia picture tutorial