Image and thumbnail services to display and alignment images using an easy syntax

Use this plugin to control the display and alignment of images using an easy syntax and support for server-side resizing and thumbnailing. There are a set of pre-defined layout formats for images as well as a free layout configurability.

Short example:

You type:

  caption="caption text"

You get:

If installed:

caption text

Images to be displayed can be located
  • at the topic as specified,
  • at the location specified in the IMAGEALBUM preference variable,
  • at the current topic or
  • at a remote URL.

If you specify a remote url using http://... the image is downloaded (using CPAN:LWP::Simple) into a local cache and then processed as usual. WARNING: please be aware of any copyrights of the images you mirror this way.

The topic and IMAGEALBUM parameters can be of the for [<web>.]<topic> . For example putting
   * Set IMAGEALBUM = %SYSTEMWEB%.ImagePlugin
into the current topic will search all images at the given topic.


%IMAGE{"foo.gif" ...}%

There are four predefined format types (plain, simple, link, thumbnail, frame, float) that can be used by setting the type paramenter (see below). In addition there is a free-form format parameter to specify any other possible html layout. The Wikipedia format is also supported. See Wikipedia:Wikipedia:Extended_image_syntax.

%IMAGE{"clear"}% will create a proper clear for floats elements.


The image name is mandatory. Further arguments are optional.

Name Values Default
align left|center|right|none none
alt alt text image filename
caption caption text empty
class (see html specs) imageFrame, imageFloat, imageResponsive, ... depending on the type
crop on/northwest/north/northeast/west/center/east/southwest/south/southeast/off: scrop the image to fit the image into the given aspect ratio; other values than on/off specify the area the croped image gravitates to relative to the original (on=center) off
data_<key; html5 data added to the image empty
desc description text title text
footer text to be appended to the html output empty
format image layout format string set by type argument
frame extract a specific frame or layer from the source file; this comes in handy when rendering a thumbnail for a video clip  
layer alias for frame  
lazyload boolean switch to enable/disable loading images lazy (if supported by the browser) off
header text to be prepended to the html output empty
height integer value image width
output image format to convert the input source to same as source image, except tiff and svg being converted to png
href hyperlink when clicking on the image url of the source image
id (see html specs) empty
mousein javascript executed if moving the mouse over the image empty
mouseout javascript executed if moving the mouse off the image empty
refresh on/off/img to trigger recomputing images off
rotate rotate image by the given dregrees keep original orientation
size geometry specification image geometry
style (see html specs) empty
title title text alt value
tooltipheight height of tooltip image 300
tooltip on/off renders an image preview in a tooltip off
tooltipcrop on/northwest/north/northeast/west/center/east/southwest/south/southeast/off: same as crop but used for the tooltip  
tooltipwidth width of tooltip image 300
topic valid topic name topic part of IMGALBUM value or current topic
transparent color to be converted to transparent  
type simple, plain, link, thumb[nail], frame, float or src plain
warn on/off, surpress error warnings on
web valid web name web part of IMGALBUM value or current topic
width integer value image width
zoom on/off to scale images, if set to "on" scaling up images is allowed, otherwise it downscales only off
filter one or more image filters to be applied to the image; see below  

Image geometry

The image geometry in the size parameter can be specified in a format <width>[px][x<height>[px]], that is width and height can be given as integers with an optional px, where the height is optional, separated with a 'x' in between. Note, that the given width and height values are the maximum width and maximum height that the image will have keeping its aspect ratio. If you want to deform it to an exact measure use the width and height arguments.

Note, that you must set zoom="on" to scale images up. Otherwise images smaller than the given geometry will stay as they are. For instance, when generating thumbnails it is preferable to keep small icons as they are instead of bloating them up to a standard thumbnail size.

Image Filters

ImagePlugin comes with a set of low-level and high-level filters that might be applied to an image. High-level filters are a combination of a set of low-level filters to immitate instagram-like modifications to the image.

Low-level fiters

  • autogamma()
  • autolevel()
  • background(color)
  • blueshift(factor)
  • blur(radius, sigma)
  • brightness(value)
  • charcoal(radius, sigma)
  • colorize(fill, blend)
  • contrast(geometry)
  • emboss(radius, sigma)
  • equalize(channel)
  • gamma(value)
  • grayscale(factor)
  • hue(value)
  • level(level, level, ...)
  • levelcolors(color1, color2, invert)
  • negate()
  • noise(value, attentuate)
  • normalize(channel)
  • oilpaint(radius)
  • posterize(levels)
  • saturate(value)
  • sharpen(radius, sigma)
  • tint(fill)

For a more thorough explanation of these filters, please read the color modifications manual of ImageMagick used underneath.

High-level filters

  • sepia(factor)
  • vignette(factor, color)
  • 1977(factor)
  • gotham(factor)
  • inkwell(factor)
  • kelvin(factor)
  • moon(factor)
  • lomo(factor)
  • nashville(factor)
  • toast(factor)
  • hudson(factor)

Example filters

  • autogamma
  • gamma(1)
  • gamma(2)
  • gamma(5)
  • gamma(0.8,1.3,1.0)
  • grayscale(33%)
  • contrast(3)
  • grayscale;contrast(3);tint(blue)
  • sepia(33%)
  • sepia,hue(33.3)
  • contrast(3);saturate(160);sepia(60%)
  • brightness(50)
  • hue(33.3)
  • level(25%)
  • level(0,75%)
  • level(25%,100%)
  • level(-25%)
  • level(0%,100%,0.5)
  • level(0%,100%,2.0)
  • levelcolors(green,gold)
  • levelcolors(,DodgerBlue)
  • levelcolors(Firebrick)
  • levelcolors(DarkGreen);autogamma
  • levelcolors(navy,lemonchiffon)
  • levelcolors(#664B19,#FFFACD);autogamma
  • normalize(Yellow)
  • noise(Uniform)
  • noise(Gaussian)
  • noise(Multiplicative)
  • noise(Impulse)
  • noise(Laplacian)
  • noise(Poisson)
  • blueshift(0)
  • blueshift(0.5)
  • blueshift(1)
  • blueshift(1.5)
  • blur(1,1)
  • sharpen(0.4)
  • charcoal(,1)
  • emboss(1,2)
  • vignette(1.5)
  • colorize(,50%)
  • colorize(blue,10%)
  • 1977(33%)
  • moon(100%)
  • moon(100%);levelcolors(navy,lightyellow)
  • toaster(100%)


Format specification

Format strings given in header, footer and format may contain the following pseudo variables:

Name Value
$align value of align argumet
$alt value of alt argumet
$caption caption text
$class value of class argumet
$data value of data argumet
$desc value of desc argument
$dollar replaced with dollar sign ($)
$height image height
$href hyperlink url when clicking on an image
$id value of id argumet
$magnifyIcon enlage-icon
$mousein value of mousein argument
$mouseout value of mouseout argument
$n replaced with a linefeed (\n)
$nop replaced with empty string
$origheight image height of the original image
$origsrc url of the original image (not the resized one)
$origwidth image width of the original image
$percnt replaced with percent sign (%)
$src image source url
$thumbfile thumbnail image file name
$style value of style argumet
$text link text to be displayed in the "link" layout type
$title value of title argument
$width image width

After the layout has been formatted any further TopicMarkup that might be contained is expanded afterwards. Note, that using $percnt and $dollar evaluation order of TopicMarkup can be changed so that arguments are expanded after the IMAGE tag has been computed, whereas the default evaluation order is left-to-right-inside-out.

REST image service

The ImagePlugin implements a REST handler process to generate thumbnails for image attachments on the fly. This handler is then called in an img tag like this:

<img src='%SCRIPTURLPATH{"rest"}%/ImagePlugin/process?

Arguments to the process handlers are:

Name Values Default
topic topic where the image is attached BASEWEB.BASETOPIC
file image filename  
crop cropping mode  
filter filter to be applied to the image  
height height of thumbnail  
refresh on/off/img to trigger recomputing images off
rotate degree to rotate the image  
size geometry of thumbnail  
width width of thumbnail  
zoom switch on/off upscaling off


  • See also Sandbox.ImagePluginFilterTest for an exhaustive sample and test page
  • Resize to 100 pixels, text flows right, with caption
    %IMAGE{"Westminstpalace.jpg" size="100" align="left" caption="This is my caption"}%
  • Resize to %THUMBNAIL_SIZE% size, and center image
    %IMAGE{"Westminstpalace.jpg" type="thumb" align="center"}%


You can turn on downloading and mirroring of images that link to external sites, Example: logo.gif

$Foswiki::cfg{ImagePlugin}{RenderExternalImageLinks} = 1;

This will download the image and mirror it on the local site. Use the refresh url parameter to check if the external images has updated.

If you also turn on attaching a mirrored image to the current topic, an additional attachment-record is generated for the downloaded external image. Attachments will be marked as hidden. Note, that any auto-attached image will update the topic and with it its timestamp.

$Foswiki::cfg{ImagePlugin}{AutoAttachExternalImages} = 1;

Installation Instructions

You do not need to install anything in the browser to use this extension. The following instructions are for the administrator who installs the extension on the server.

Open configure, and open the "Extensions" section. "Extensions Operation and Maintenance" Tab -> "Install, Update or Remove extensions" Tab. Click the "Search for Extensions" button. Enter part of the extension name or description and press search. Select the desired extension(s) and click install. If an extension is already installed, it will not show up in the search results.

You can also install from the shell by running the extension installer as the web server user: (Be sure to run as the webserver user, not as root!)
cd /path/to/foswiki
perl tools/extension_installer <NameOfExtension> install

If you have any problems, or if the extension isn't available in configure, then you can still install manually from the command-line. See for more help.


Foswiki::Plugins::ZonePlugin>=1.0Required for Foswiki < 1.1

Change History

26 Oct 2020 added support for native lazy loading of images; rewrite caching of image metadata using Foswiki:Extensions/CacheContrib
12 Nov 2019 performance fixes, i.e. caching ping results; don't render local images by default; fixed processing transparent background; fix file permissions of thumbnails; svgs are images too; pptx, docx, odt and xlsx files are "frameish" as well to ease thumbnailing them; use svgs in tooltips as is, don't resize them
11 Jun 2018 add src option to type parameter to access the thumbnail source being generated
05 Mar 2018 fixed cleaning up old thumbnails of images with brackets in them; added transparent feature; up'ing density converting svg images
09 Sep 2017 fixed filter api; really default crop to off
27 Jul 2017 removed support for Graphics::Magick ... not worth it and not a 100% drop-in replacement; performance: don't deliver image blobs by itself, use a redirect instead; removed support for xsendfile protocol as we are redirecting now; improved method to delete unused thumbnails; added support to generate a cover image of a video; better support for gallery renderers (photoswipe, prettyphoto, ...); don't process literal blocks; renamed resize rest handler to process (former still there for compatibility)
11 Oct 2016 added image filters with instagram-like presets
31 May 2016 added mime type detection for inline image data that don't specify it; improved support for html5 data
06 Apr 2016 fixed attaching inline data images
01 Apr 2016 fixed resize rest handler returning invalid image data; working around buggy implementations of imagemagick core-dumping on exit
26 Sep 2015 fixed rewrite of html img tags to bail out when width/height units aren't px values; don't auto-render svg to png anymore
17 Jul 2015 optionally extract and convert inline svg to real images; optionally process html img tags and downscale them on the server; add support for Foswiki-2.x
16 Dec 2014 work around call to unofficial internal api to get absolute pub urls; support extracting thumbnails from movies (mp4,mov,m4v,mpeg,mpg and wmv)
17 Sep 2014 added feature to convert inline image data to proper attachments
08 Sep 2014 added rotate parameter
04 Sep 2014 implemented frame and layer parameter for thumbnail extraction from videos, animations and layered images
28 Aug 2014 only render the first frame of a gif animation generating thumbnails; fix orientation of thumbnail as specified in the EXIF metadata; fully specify REST security flags; new parameter output
28 May 2014: fixed thumbnail handling in afterRenameHandler
16 Apr 2014: brought back thumb image type
04 Apr 2014: flag rest handlers that don't require authentication
18 Mar 2014: support blanks in image names
3 Aug 2013: rework image tooltip code to use jquery-ui instead of deprecated jquery.tooltip
8 May 2013: return a 1x1 pixel when calling the image rest handler for a non-existing image
24 May 2013: update thumbnails whenever a new image of the same name was uploaded
6 May 2013: some more svg fixes; cleaning up thumbnails now when images are renamed or moved
9 Oct 2012: added svg support
6 Aug 2012: respect noautolink tags when rendering external image links
25 Jun 2012: fixed attaching external images to the right topic; removed unused option AutoAttachThumbnails; fixed processing of non-attached external images; fixed downloading of urls that look like image links but return a different content type
09 Jan 2012: added new option 'thumbfile' to format string (Foswiki:Main/JoenioCosta); speed improvement by not "ping-ing" each image on display; rendering thumbnails using newer method available in image::magick 6.5.x, the old method faild resizing and cropping on some platforms; removing longdesc from default image templates; now also caching urls to external images that include url params
29 Jun 2011: fixed detection of image links to the own wiki not to try an external download+mirror
10 Jan 2011: fixed parsing of mediawiki like params; fixed jquery interface to foswiki preferences; fixed dependency on ZonePlugin to only be required for old foswiki versions; make result of resize REST service cacheable, i.e. don't use a redirect; fixed expansion of standard escapes; improved crop parameter to specify the location of the remaining image relative to the original; added data parameter to interface with jquery code; using md5 now to properly cache thumbnails; mirroring external images now obeys the ATTACHFILESIZELIMIT preference;
12 Feb 2010: made imagetooltip a proper jQuery plugin; using Foswiki:Extensions/ZonePlugin for faster page loads
17 Nov 2009: added zoom parameter; fixed manual refresh via url params
24 Sep 2009: updated imageplugin.template to help XHTML validation (stop rendering empty id attribute)
14 Sep 2009: using Foswiki's proxy settings instead of ENV; disabled tooltip previews for Internet Explorers
18 Aug 2009: removed bonus % in template (Foswiki:Main.AndreLichtsteiner, Foswiki:Main.WillNorris)
24 Apr 2009: converted to foswiki plugin; added thumbnail REST handler; added tooltip preview using jquery; added mirroring of external images; moved image type definitions into a template
11 Feb 2009: updated documentation examples (Foswiki:Main.WillNorris)
07 Jan 2009: certified for foswiki/compat
03 Jul 2008: fixed parsing the type parameter; fixing docu about the default THUMBNAIL_SIZE; added new default format plain; plainify text to be used in a html attribute position, e.g. titles; default to no img alignment; refresh images on a ?refresh=on url param; using LWP::UserAgent instead of LWP::Simple to mirror images; using Resize instead of Scale for higher quality thumbnails; don't encrypt the href param
03 Mar 2008: make implementation of image mage configurable, defaulting to Graphics::Magick as Image::Magick has got issues using perl accellerators like mod_perl, speedy-cgi
03 Jan 2008: added processing of remote images
18 Dec 2006: fixed image lookup order; fixed html formats; added I18N workaround
18 Aug 2006: fixed html errors; removed references to ImgPlugin thus not showing the magnify-clip; some html and css fixes to resemble closer to the MediaWiki examples
17 Aug 2006: width and height arguments had no effect; floating images not clearing proberly on IE
16 June 2006: released into the public
10 May 2006: Initial version by forking ImgPlugin

PackageForm edit

Author Craig Meyer, Michael Daum
Version 10.00
Release 26 Oct 2020
Description Image and thumbnail services to display and alignment images using an easy syntax
Copyright © 2006, Craig Meyer, © 2006-2020 Michael Daum
License GPL (GNU General Public License)
Home Foswiki:Extensions/ImagePlugin
Support Foswiki:Support/ImagePlugin
Topic revision: r1 - 12 Nov 2019, ProjectContributor
This site is powered by FoswikiCopyright © by the contributing authors. All material on this site is the property of the contributing authors.
Ideas, requests, problems regarding Foswiki? Send feedback