Thumbnail size in Jira cannot be bigger than 200x200px

Summary

As per the documentation - Configuring file attachments, users are allowed to configure the thumbnail size. However, changing the thumbnail width and height to anything bigger than 200x200px does not reflect on the UI. Note that, the thumbnail(s) under $JIRA_HOME/data/attachments/<project-key>/10000/<issue-key>/thumbs are generated with the correct dimensions.

Steps to Reproduce

1. Open $JIRA_HOME/jira-config.properties
2. Edit (or add) the values of the following properties with values greater than 200

   jira.thumbnail.maxwidth = 300
   jira.thumbnail.maxheight = 300

3. Delete all existing thumbnail images within the attachments directory (that is, those containing 'thumb' in the filename)
4. Restart Jira

Expected Results

Thumbnails in Issue are resized accordingly to the new maxwidth and maxheight values.

Actual Results

No changes observerd to the thumbnail size in the issues.