Working with Images

This website contains links to software which is either no longer maintained or will be supported only until the end of 2019 (CKFinder 2). For the latest documentation about current CKSource projects, including software like CKEditor 4/CKEditor 5, CKFinder 3, Cloud Services, Letters, Accessibility Checker, please visit the new documentation website.

CKFinder allows you to create thumbnails and to scale uploaded images to the preferred size.

This section describes working with images. It will provide you with the information on how to properly configure thumbnails and image resizing options. Note that without the GD library CKFinder will be unable to resize images and the thumbnail feature will be disabled.


You can set thumbnails parameters by changing the following values:

$config['Thumbnails'] = Array(
'url' => $baseUrl . '_thumbs',
'directory' => $baseDir . '_thumbs',
'directAccess' => false,
'bmpSupported' => false,
'enabled' => true,
'maxWidth' => 100,
'maxHeight' => 100,
'quality' => 80);
  • maxWidth and maxHeight – determine the maximum size of the thumbnails which can appear in CKFinder. These values are defined in pixels. You can obviously increase them, but the thumbnails will then look more like full-sized images than like miniatures.
  • quality – sets the quality of a thumbnail in a range from 1 to 100. The smaller the quality value, the smaller the size of the thumbnail. Notice that an acceptable quality value is about 45 and the most frequently used one is about 80.
  • directAccess – this setting may increase the overall performance of CKFinder. By default, CKFinder connects to the server connector to get the thumbnail. It is not a problem in most cases, because the connector sends the HTTP/304 Not Modified header most of the time to save the traffic and reduce server-side processing. However, sometimes it is better to leave cache control to the browser. When directAccess is set to true, thumbnails are loaded directly from the _thumbs folder by CKFinder. Note that it is impossible to use this setting, if the thumbnail directory is located outside the document root.
  • bmpSupported is a setting available only in the PHP connector, because the GD library in PHP does not support the .bmp format. It is possible to enable support for .bmp files in CKFinder. In this case CKFinder will use a special PHP class to manipulate such images. Because resizing of .bmp files is relatively slow, this feature is disabled by default.
  • You may disable thumbnails by placing the bool value false in the enabled section.


The scaling (resizing) option allows you to define the maximum size of uploaded images. If the image size is bigger than the one specified by you, the image will be scaled to the defined dimensions.

You can also change the quality of uploaded images by setting it in a range from 1 to 100. To apply these options you should change the following configuration settings:

$config['Images'] = Array(
'maxWidth' => 1600,
'maxHeight' => 1200,
'quality' => 80);
This page was last edited on 29 March 2011, at 15:19.