&lt;p&gt;The thumbnail images can be generated automatically by checking the &lt;strong&gt;Auto Generate Thumbnails for New Images &lt;/strong&gt;feature in the&lt;strong&gt; &lt;/strong&gt;Media Configuration. By using this feature, the thumbnail images will automatically be generated according to the&amp;nbsp;specified reduction setting&amp;nbsp;when new media are brought into the system using the Auto Detect feature. Otherwise they can be generated (or re-generated) using the method outlined below.&lt;/p&gt;
&lt;p&gt;This page is used to generate thumbnails for the target category. All categories that are currently residing in the database will be displayed here. To sort the category listings, click on the hyperlinked column titles. You can reverse the displayed sort order by clicking on the same link again.&lt;/p&gt;
&lt;p&gt;If you want to use the system&#039;s &quot;Generate Thumbnails&quot; feature, you should convert all display images to jpg format (or .gif or .png if your server&#039;s GD version supports them) before uploading them to the server. Alternatively, you can upload other file types with a pre-made thumbnail. Remember to upload the thumbnail to the same directory and give the thumbnail the admin defined thumbnail prefix, which is gallery_ by default.&lt;/p&gt;
&lt;p&gt;Click on the &lt;img src=&quot;images/admin/apply.gif&quot; alt=&quot;&quot; width=&quot;16&quot; height=&quot;16&quot; align=&quot;top&quot; /&gt; icon for the target category to generate thumbnails. The thumbnails for the entire category of images will be created based on the&amp;nbsp;reduction setting in the Media Configuration section.&lt;strong&gt; &lt;/strong&gt;Before using this feature, you must ensure that all image folders have permissions of 777 (r/w/e)&lt;/p&gt;
&lt;p&gt;After this action completes, the status for the target category will change from Not Generated to Generated&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; If there are a large number of images in the directory, the execution may timeout, this is not a fault in the system. Just click on the browser refresh button and the system will continue to generate thumbnails from where it left off. Keep doing this until you see the Action performed successfully message. If you do not see this success message, check to see if the thumbnail overwrite box in the configuration section is checked. If it is, uncheck the box and click on the generate thumbnails link again.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Video and other formats of display media&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;If the media is video, audio or another format of display image, you will need to create a thumbnail image for the display media and upload it to the same directory where the display file is located.&lt;br /&gt;&lt;strong&gt;Example: &lt;/strong&gt;&lt;br /&gt;Media system name: &lt;strong&gt;video1.mpg&lt;/strong&gt; (this is a video type)&lt;br /&gt;The thumbnail prefix name: &lt;strong&gt;gallery_&lt;/strong&gt; (this can be set in the Media Configuration section) &lt;br /&gt;Then the thumbnail for this media should be &lt;strong&gt;gallery_video1.jpg &lt;/strong&gt;&lt;br /&gt;Upload this thumbnail to the directory where the video1.mpg is located.&lt;/p&gt;
&lt;p&gt;&amp;nbsp;&lt;/p&gt;