Default image setting

I've imported several hundred users into CB and am starting to develop lists to display them by category. One of my fields (cb_logo) is for the members to upload their company logo, which some do and some don't.  My question is how can I set a default image to replace the black silhouette that would appear in the lists?  Please see:  a2zpreview4.com/accountants-and-bookkeepers . This would need to be both for new registrations and for the imported ones.

Thanks

Edit your image field and under Parameters > Image Display you can set the defaults. New images can be added to the following folder.

/components/com_comprofiler/plugin/templates/default/images/avatar

Thanks, just setting it to null when nothing is entered is what I was looking for!