Microsoft released an update to Lync 2013 Windows Client, which have option to users to eliminate the images of senders and receivers in IM conversations without disabling them in the contact list.
Microsoft also included all of IM options in the Option dialog to make them easier to find and made a number of other improvements to our media stack to improve call quality wherever you are.
Microsoft further refined this option by adding the ability to disable pictures in the IM conversation Windows only.
Many of us wondering how do I set the option, in this release Microsoft combined all IM related settings on their IM tab under Lync-Option, shown below, including the new, Hide picture in IM setting. This simplifies the General tab and provides an easy way to find all IM windows related features.
You can see the October 2014 update for Lync 2013 for the complete set of details and to download the new update.