How to change thread Thumbnail ?

Hi there. I’m kinda new here and I startet a new thread here:

But didn’t know that thubnail will be chosen automaticly. Now I would like to chose other image, because the existing thumbnail dosen’t show actual project I wanted to show :confused:

Any one knows how to change it ?

The thumbnail is the first image attached to the first post in the thread. Just change that image to change the thumbnail

Edit Post / Go Advanced / Manage Attachments

There may be an image cache (either locally on your machine or with the CDN we use). Try doing a “hard refresh” (Ctrl+Shift+R) in your browser. If that doesn’t work, it may be on the CDN side (or something else entirely, but that’s my best guess)

It definitively doesn’t change when changeing the order of the two pics in my thread.

Is there something broken or am I doing anything wrong?