Good observation, there is default image displayed when header image is not uploaded for any Space/Project.

It's the default thumb when not set the banner image. We will update it to be clearer. @mrbaar

<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-image-off h-5 w-5 text-white/60"><line x1="2" x2="22" y1="2" y2="22"></line><path d="M10.41 10.41a2 2 0 1 1-2.83-2.83"></path><line x1="13.5" x2="6" y1="13.5" y2="21"></line><line x1="18" x2="21" y1="12" y2="15"></line><path d="M3.59 3.59A1.99 1.99 0 0 0 3 5v14a2 2 0 0 0 2 2h14c.55 0 1.052-.22 1.41-.59"></path><path d="M21 15V5a2 2 0 0 0-2-2H9"></path></svg>