I've read through the material on display modes. While it is very comprehensive, it does border on being too much so, and therefore not easy to use.
I used to have the display automatically switch to "thumbnail" mode when a folder of JPEG files was opened. And when a folder of non image files was switched to, the display mode went back to details.
I would like to get that mode back. But it is not clear how to accomplish this.
Ron Hirsch
To do that you need to enable Folder Content Type detection, under Preferences - Folders - Options, and then ensure that the Images content type format is enabled under Preferences - Folders - Folder Formats.
(This is assuming you haven't modified the Images content type or the list of extensions which are associated with the type.)
Hi Leo,
Thanks again. One of the "required" checkboxes was not checked.
The problem is resolved.
Keep up the good work, 
Ron