Select language:

 Thumbnail Repository Manager


This repository manager generates thumbnails of resources at runtime. It uses plug-ins to do this. The generated thumbnails can be displayed in the explorer instead of symbols.


The thumbnail of an object is treated as a predefined property on the user interface: rnd:thumbnail(Modifier1/Modifier2/...). For more information, see Displaying Properties .

You can use the Thumbnails layout profile to display thumbnails in the explorer. For more information, see Defining the Display of Folders .

Thumbnails are displayed in a selection dialog box for images.


Plug-ins for generating thumbnails already exist (see Plug-Ins for Thumbnails ).


Generating and Storing Thumbnails

As soon as a user opens a folder containing resources for which thumbnails can be generated in the explorer, the repository manager uses plug-ins to generate corresponding preview images of these resources. The service user cmadmin_service is used to generate the images.

During the generation of the thumbnails, symbols continue to be displayed in folders that are called up in parallel. When the generation has finished, the thumbnails appear instead of the symbols when you update the iView.

The preview images are stored in the CM repository /~system/thumbnails.  A separate folder is created there for each required size.


If you use thumbnails that are 100 pixels high and 100 pixels wide, the thumbnails are stored in /~system/thumbnails/100x100.


The thumbnails are retained if a single resource is deleted.

If you are no longer using thumbnails of a certain size, you can delete the corresponding folder.


Before generating a thumbnail the repository manager checks whether a thumbnail of the required size already exists in /~system/thumbnails. If the check reveals that the object has been modified, a new thumbnail is generated.

When a folder than contains thumbnails is called up, the browser firstly loads the HTML text and then the thumbnails are loaded from the system folder. This means that you can continue with navigation even if the thumbnails have not yet been fully loaded.

The generation of a thumbnail is terminated automatically if more than 60 seconds is needed.

The content of objects is loaded to the working memory of the portal server for the generation of thumbnails. To restrict the amount of memory that is needed, you can define a maximum file size for objects from which thumbnails can be generated. You do this in the configuration of the plug-ins. If the object is larger than the defined size, no thumbnail is generated. Instead, the default symbol is displayed in the explorer.


The repository manager for thumbnails only generated thumbnails for objects for which the user has permissions.


The following parameters are relevant for the configuration of the repository manager:

Parameters for Thumbnail Repository Manager

Parameters Required Description

CM Repository Folder RID


Folder in which the thumbnails are stored.

Default: /~system/thumbnails



Description of the repository manager.



URI prefix of the repository manager

Default: /thumbnail



You can (de)activate the repository manager using the Active parameter.

Display Thumbnails instead of Icons


Specifies whether or not thumbnails are displayed.

You can use this parameter to deactivate all thumbnails in KM. 

Hide in Root Folder


Specifies whether the repository is listed in the root directory.

By default this parameter is activated (the repository is not listed in the root folder).

Send Events


Specifies whether the repository sends events when operations such as delete and update content are performed.

By default, this parameter is deactivated.

Property Search Manager


Selection of manager for property search.

By default, no manager is needed.

Default Thumbnail Height


Specifies the standard height of thumbnails.

Default Thumbnail Width


Specifies the standard width of thumbnails.

ACL Manager Cache


Cache for resource ACLs.

By default, no cache is needed.

Security Manager


Security manager that controls access to repository content. For more information, see Security Managers

By default, no security manager is needed.



The repository manager is preconfigured in the standard delivery. No further configuration is necessary.

To check the configuration of the repository manager, choose Content Management →Repository Managers → Thumbnail Repository.