I am trying to create an edit Interface for a custom module. I want to use a file picker, and found some different sources, but nothing seems to work really. Here is a code snippet:

and here is what comes out (in a popup window):

Can anyone tell me:

1.  What is the difference between a DnnFilePickerUploader, a DnnFilePicker, and a "dnn:FilePickerUploader" (as I find it in /DesktopModules/Admin/Portals/SiteSettings.ascx)?
2. How to implement any of these controls in a way that it does not look as jumbled as here?
3. Why there is a DIV tag rendered inside a SPAN tag when I use the DnnFilePicker?
4. Why I always get an "object reference not set to an instance of the object" error when I am using a DnnFilePickerUploader?

Thanks a lot for your help!

Best wishes
Michael

OK, what I found out:

the dnn:FilePickerUploader is a web user control placed in the ~/controls directory. Using this looks nice enough:

My next questions:

1. I am pretty sure that the "Drop File(s) Here" does only work in an intranet. How can I hide this, and only show a thumbnail of the picture (if there is already a picture selected)?
2. How can I hide the "Folder" and "File" item and only give the possibility to upload a new file which will be automatically selected after upload to a given directory, or show a thumbnail of a file that is already there (when the form is in "Edit" mode or the file has been uploaded)?
3. Is there a way to "clear" the selection?

Best wishes
Michael