Exchange 2013 cu10
as we are uploading user photos, i use the AD attribute "thumbnailPhoto" to store user's pics. there are some who, even though i've uploaded their picture, what shows in Outlook is different from what was uploaded. upon further checking, i found that the photo in OWA, which the users uploaded themselves, are taking precedence of the AD attribute.
is there a way to delete this OWA photos aside from doing it directly from user's OWA? like what's the attribute name so that i can assign NULL to it?