Described herein are systems and methods for transporting an electronic communication that includes one or more attachments efficiently by sending the electronic communication with a smaller-sized (e.g., lower resolution) representational element of each attachment and subsequently replacing each representational element with a higher resolution attachment thumbnail of the attachment. The high resolution attachment thumbnail is produced in an asynchronous process during or after the transportation of the attachment(s) and the electronic communication. After the high resolution attachment thumbnail(s) is generated, at least one representational element in the electronic communication may be replaced with a corresponding HR attachment thumbnail.