Enabling Thumbnails for Attachments

'Thumbnails' allow an image to be previewed in miniature, without having to download the original full-size image. JIRA can automatically create thumbnails for file attachments of the following types:

• GIF
• JPEG
• PNG

Once thumbnail functionality is enabled, thumbnails are displayed to users in the 'Image Attachments' section when viewing an issue. (All other types of file attachments are listed in the File Attachments section.) You can also configure the Issue Navigator column layout to display the thumbnails in an Images column.

All thumbnail images are stored in JPEG format in the attachments directory (see ' Configuring File Attachments '), together with the original attachments. The thumbnail images are denoted by ' thumb ' in the filename.

Enabling thumbnails

1. Log in as a user with the 'JIRA Administrators' global permission.
2. Bring up the administration page by clicking either the 'Administration' link on the top bar or the title of the Administration box on the dashboard.
3. Under the 'Global Settings' sub-menu in the left-hand navigation column, click the 'Attachments' link. This will display the 'Attachment Settings' page, which states whether attachments are currently on or off.
   • Note: attachments must be enabled in order to enable thumbnails. Attachments can only be enabled by people who have the 'JIRA System Administrators' global permission.
4. Click the 'Edit Configuration' link.
5. In the 'Enable Thumbnails' field, select 'ON'.
6. Click the 'Update' button.

Configuring thumbnail size

By default, thumbnails are 200 pixels wide and 200 pixels high. To change the dimensions of thumbnail images:

1. Stop JIRA.
2. Edit the following values found in the file jira-application.properties :
   • jira.thumbnail.maxwidth
   • jira.thumbnail.maxheight
3. Delete all existing thumbnail images within the attachments directory (denoted by '*_thumb_*' in the filename).
4. Restart JIRA. All thumbnails will be automatically recreated using the new dimensions.