Does your community use LDAP to sync profile images? Or are there any manual API tasks running which could be pulling the images from an external service such as your Active Directory?
If your community does not currently have the profile image sync enabled with your LDAP, I would encourage you to open a support case within your Private Support Group (MyJive Group https://community.jivesoftware.com/support.jspa). This would allow Jive Support to further review your environment and look over the settings within your community.
Hope this helps.