A method of controlling an operation of a display device is described. The display device includes a memory including a self-refresh memory block, a display module and a controller configured to control the operation of the display device. The controller is configured to receive a power-off signal, store a system booting file and a predetermined snapshot image in a self-refresh memory block based on a predetermined self-refresh mode, receive a power-on signal, boot a system by extracting the system booting file from the self-refresh memory block, and control the display module to display the predetermined snapshot image. A content is contiguously displayed by the display module when the power-off signal is received. An image configured by default is displayed by the display module after the power-on signal is received. A specific content is executed which is selected according to a user access frequency.