Page tree
Skip to end of metadata
Go to start of metadata

The Imaging module simplifies working with images. You don't need to resize and crop each image by hand as the imaging engine generate variations on-the-fly. Administrators create the rules that determine the sizes of derivatives. Editors save time as they can select an image from the DAM or upload one, and it will be automatically adapted to match the rule.

Please note that the artifact's IDs (Maven groupId and artifactId) have changed since Magnolia 5.5.

If you have custom Java code relying on this module, you need to install a compatibility module too.

To be sure - please check the module on our Bitbucket server.


Maven is the easiest way to install the module. Add the following to your bundle:

Note the changes in groupId and artifactId since the 3.4 release.


Compatibility module

With Magnolia 5.6 we've begun removing the old Content API from our modules. If you have custom code relying on classes from the old imaging module then you must do one of two things:

  • Update your code for the new version of the imaging module.
  • Or you can use the magnolia-imaging-compatibility module together with the magnolia-core-compatibility module.
 Click here to expand to see how to add the compatibility module

Add the following snippet to your pom file:


Image request processing

The diagram shows the elements of the Imaging module and how they interrelate (credit: Richard Unger).

  • ImagingServlet is responsible for the actual generation of the images.
  • ImageGenerator interface is the entry point for generating images .
  • ImageOperationChain  implements ImageGenerator and executes an operation chain .
  • Various implementations of ParameterProviderFactory  interface are responsible for instantiating parameter providers for a given environment.
  • Implementations of ImageStreamer  interface are responsible for pushing the generated image, with the given generator and parameters, to an output stream.

Imaging servlet

ImagingServletis registered in the Magnolia servlet filter chain in /server/filters/servlets/ImagingServlet. The servlet is responsible for generating images.

Image generators

ImageGenerator is a component that generates variants from a source image based on configuration. Generators are used by image provider classes to render images in the UI and on pages. 

Generators are configured in /modules/imaging/config/generators.

Example: Generator configurations:




Generators configuration.

<generator name>


The name of the image generator.

large, portrait and thumbnail are used in the UI to generate images in apps. mte generates image variations in a theme.



The image generator class:

  • DefaultImageGenerator: Default image generator with provided OutputFormat and ImageOperation defaults.
  • ImageOperationChain: Image generator that delegates to a list of ImageOperation instances. This is the most commonly used generator class. It executes an operation chain and is used by largeportrait and thumbnail generators.
  • ThemeAwareImageGenerator: Theme-aware generator that handles image variations in a theme. Extends ImageOperationChain.



Output format configuration.



See the Parameter provider factory class.


required *for image operation chains

See the Image operation chains configuration.

Output format

The output format is the format or file type the generator produces, such as JPEG or PNG. Supported formats are bmpgifjpegjpgpng, and wbmp. The module also supports these formats and tiff as input formats . You can verify the available formats on your system by installing the magnolia-module-imagingtools.jar The Image I/O plugins app displays a list of supported file extensions.

The output format is configured in /modules/imaging/generators/<generator name>/outputFormat.

Examples: Output format configurations.




Output format configuration. Defines the format the generator produces, such as jpg or png.



Image quality as a percentage.


required *for ImageOperationChain only

The file extension of the generated images.

ThemeAwareImageGenerator generates images in the same format as the source image. If you upload a jpg, this generator will produce a jpg.

Parameter provider factory

Parameters are instructions passed to an operation, such as where to load a source image or what text to lay over it. Registering a ParameterProviderFactory allows you to pass parameters from different sources:

The parameter provider factory is configured in  /modules/imaging/generators/<generator name>/parameterProviderFactory.

Parameter provider classes:


Node-based  ParameterProviderFactory  that tries to determine the  Node  by its identifier.


Node-based  ParameterProviderFactory  that will tries to determine the  Node  by its path.


Theme -aware ParameterProviderFactory .
info.magnolia.imaging.parameters.AbstractWorkspaceAndPathParameterProviderFactorySuperclass for parameter provider factories based on workspace and path.
info.magnolia.imaging.parameters.AbstractWorkspaceAndIdentifierParameterProviderFactoryExtracts workspace and identifier from the path. Everything after the identifier is ignored. This allows you, for example, to pass a properly named file name, to the image.
info.magnolia.imaging.parameters.AbstractWorkspaceAndUuidParameterProviderFactoryExtracts workspace and UUID from the path. Everything after the UUID is ignored. This allows you, for example to pass a properly named file name to the image.

Image operation chains

The Imaging module can resize and crop images, overlay text and apply image filters. These are called image operations and are configured in  /modules/imaging/config/generators/<generator name>/operations. Image operations can also be configured in a theme.

An image operation chain consists of one or more operations. A simple chain could add only fixed text, while a more complex chain could load an image from a remote source, apply filters, add multiple text fields and style them differently.

Example: Image operation chain configuration:


<generator name>


Name of the image generator.



Operations node.

<operation names>


One node for each operation in the chain, for example load, resize and overlay. The chain is executed from top to bottom.



Operation class



Other properties supported by the operation class.

The first operation in an operation chain is typically a load operation. Use load class  FromBinaryNode  to load an image from the DAM.

ParameterProviderFactory and load operation class typing

Note that ParameterProviderFactory and ParameterProvider implementations are typed. Let's have a look at the interfaces:(warning) Return type of ParameterProviderFactory#newParameterProviderFor and the method argument in the class used for a load operation must have the same type!

For instance BinaryNodePathParameterProviderFactory (as ParameterProviderFactory) and FromBinaryNode work nicely together.

Creating a custom generator

You can create a custom image generator If the defaults do not meet your requirements:

  • Subclass ImageOperationChain.
  • Override getOutputFormat() method.
  • Set the value of the class node in configuration to your class' name.

Imaging workspace

The imaging engine stores generated images in the imaging workspace

The path where generated images are stored depends on the CachingStrategy. The default path is:

    /<path of node or property (nodedata)>

For the MTE generator, the path is:

      /<path of node or property (nodedata)>

For example:

             /generated image

When the image is rendered on a page, the URL to the generated image is:

/<CATALINA_HOME, contextPath>
  /.imaging (which is the Imaging servlet default path)
      /<path to the cached image>

Here's the same image generated by the portrait and mte generators in the JCR Browser app. The 960x720 variation is configured in the travel-demo-theme

Viewing generated images

The syntax for the URL to request a generated image depends on the used ParameterProviderFactory. However, it usually has the following pattern:

<protocol>://<context>/.imaging/<generator name>/<specific parameters ...>

Here is an example of a path when using BinaryNodePathParameterProviderFactory


Example: http://localhost:8080/magnoliaAuthor/.imaging/custom-generator-2/dam/examples/jimi-hendrix.jpg/jcr:content.jpg


Magnolia caches image resources to improve performance. Any dynamic images generated by the Imaging module are cached at two levels: in the imaging workspace and in the actual cache like any other page or document. This means that once the system generates an image, you keep getting the same cached image on subsequent requests.

During testing, you can disable caching of generated images completely. In /modules/imaging/config , create a new property storeGeneratedImages, and set the value to false.

(warning) There is still a small delay between configuration changes and a new image being available. Magnolia's observation mechanism intentionally waits a couple of seconds before reading a changed configuration.

Imaging support

Imaging support is enabled by 3 Magnolia modules:



The support interface for imaging.


Asset renderer that uses ImagingSupport to generate renditions.


ImagingSupport that delegates to a Theme.

Image variations in a theme

A variation is a theme-specific configuration that defines the size of the target image and tells the imaging engine whether cropping is allowed. Variations are configured in a theme which allows you to configure image look and feel  in the same place as CSS.

See Image variations and Displaying resized images for more.

Configuring an image operation in a variation