Description of Problem

In Jira 8.x, the thumbnail images are likely stored in PNG format.

# file /var/atlassian/application-data/jira/data/attachments/AAA/10000/AAA-9/thumbs/_thumb_10000.png
/var/atlassian/application-data/jira/data/attachments/AAA/10000/AAA-9/thumbs/_thumb_10000.png: PNG image data, 200 x 133, 8-bit/color RGB, non-interlaced

However, in this document, it is said that all thumbnail images in Jira are stored in JPEG format.

Configuring file attachments

All thumbnail images are stored in JPEG format in the attachments directory, together with the original attachments. The thumbnail images are denoted by 'thumb' in their file names.

The document should be fixed.

Suggested Resolution

The document should be fixed like this.

Configuring file attachments
> All thumbnail images are stored in PNG format in the attachments directory, together with the original attachments. The thumbnail images are denoted by 'thumb' in their file names.