1. A printing system including a printer and a terminal device connected to the printer, the terminal device comprising: a first data transmitting unit configured to transmit print data and a layout data request to the printer, the layout data request requesting the printer to transmit layout data representing an arrangement of objects to be printed on a print sheet if the printer would print the print data; the printer comprising: a first data receiving unit configured to receive the print data and the layout data request from the terminal device; a layout data generating unit configured to generate the layout data based on the print data in response to the layout data request; and a second data transmitting unit configured to transmit the layout data generated by the layout data generating unit to the terminal device, the terminal device further comprising: a second data receiving unit configured to receive the layout data from the printer; a preview image generating unit configured to generate preview image data representing a preview image showing a result of printing if the print data would be printed on the print sheet in accordance with the layout data; and a display unit configured to display the preview image represented by the preview image data generated by the preview image generating unit.