File type does not change toolbar

I was trying to set up a toolbar for image manipulation that only appears, if images (=Bilder) are the main file type in a folder:

Unfortunately this does not work. For better control I also set the tab color to change, but also this does not happen.!Documents/Content_Types.htm

I have acitivated this option already. This is why I am so confused.

We need more detail. What is in the folder? What does the status bar say the current folder format is and where does it say it comes from? (See the Folder Formats FAQs if you’re unfamiliar with how to get that information.)