Outlook 2013 from Office 365

Hi

So we have locally deployed office 2013 from the office 365 and all is going well so far. We also introduced profile pictures of staff which they find great when using Lync but find quite annoying when they are sending and receiving email to and from one another. I understand this profile photo does not go with external emails its just for users on the GAL but is there anyway of not having the profile picture on emails that users send and receive? Take for example an email thread going on for over 5 emails users end up not wanting to see the others all the 5 times.

Its probably an all or nothing thing but just thought i would ask as it great in Lync.

Thanks