#create a DTML Method called, uploadForm
<form method="POST" action="processForm" enctype="multipart/form-data">
  Id: <input type="text" name="id" value="" /> <br />
  Title: <input type="text" name="title" value="" /> <br />
  File or Image: <input type="file" name="file" value="" /> <br />
  <input type="submit" name="save" value="Upload" />
</form>

#Way 1.  The DTML Route
#create a DTML Method called processForm
<dtml-call "REQUEST.set('file_type', file.headers['Content-Type'] )">
<dtml-if "file_type.find('image')!=-1">
    <dtml-call "this().manage_addImage(REQUEST['id'], file, REQUEST['title'])">
<dtml-else>
    <dtml-call "this().manage_addFile(REQUEST['id'], file, REQUEST['title'])">
</dtml-if>    
Finished

#Way 2. The Python Route
#in Script (Python), called processForm
#parameters: id, file, title=''
REQUEST=context.REQUEST
content_type=file.headers['Content-Type']
if content_type.find('image')!=-1: #.find() is a method in Python2.0<
    context.manage_addImage(id, file, title)
else:
    context.manage_addFile(id, file, title)
return 'Finished'