In addition to the Wintersday update, the equipment preview system has also changed. You will not be able to preview equip link players send in chat window directly. Maybe you are not comfortable with the change of equipment preview system. But don’t worry. The system will be back soon. They just delete it in order to solve and improve some functional problems.
ArenaNet says they are working hard to improve the equipment preview system. Thus they have to disable some functions for the time being. However, the equipment preview system will be back in the coming patch.