You can only remove the image file from a profile if you are the profile owner or an administrator.
To remove a photo from a profile, complete the following steps:
1. Get the service document for the person's profile. See Retrieving the Profiles service document
2. From the service document, get the URI for the profiles feed which is specified in the href attribute of the collection element and use it to get the profiles feed for the user.
3. In the returned feed, find the link where the rel attribute has the value "http://www.ibm.com/xmlns/prod/sn/image" .../>. Alternatively, use the URI specified in the "Request Details" table below.
4. Use this link to send a DELETE request to remove the image file.