How to define the folder that is opened by default?

Hello, i just want to force the user to pick an image from a set folder with File Field Sources and the IMCE option.
So i want to get ride of the navigation part of the file browser and to be able to define which folder is opened by default for that field.

Note i also use imce for WYSIWYG editor and there i want to leave it all available.

Thanks in advance