[Theme Tempest]

All the status icons—both for the forum and threads—are located in the "images/statusicon" folder, unless the folder location for your theme was changed in the "Image Paths" settings in the Style Manager.

All you need to do is create new images and give them the same name as the default ones, then upload them to your server in the "statusicon" folder, overwriting the old ones. Alternately, you can create a new statusicon folder, upload the images to it, and enter the path to the folder in the "Item Status Icon Folder" field under the "Image Paths" section.