A method of controlling an operation of a display device , the method comprising: receiving (S1810) a power-off signal; storing (S1830) a system booting file and a predetermined snapshot image in a self-refresh memory block based on a predetermined self-refresh mode, wherein the predetermined snapshot image corresponds to at least one of an image of a content data, a default image and a specific content image; and wherein the predetermined self-refresh mode includes a first predetermined self-refresh mode , a second predetermined self-refresh mode ; and a third predetermined self-refresh mode ; receiving (S1840) a power-on signal; booting (S1850) a system by extracting the system booting file from the self-refresh memory block ; and controlling, by a controller , a display module in the display device to display (S1860) one of the predetermined snapshot images based on one of the predetermined self-refresh modes, wherein the content data is contiguously displayed by the display module when the power-off signal is received based on the first predetermined self-refresh mode , wherein the default image is displayed by the display module after the power-on signal is received based on the second predetermined self-refresh mode, wherein the specific content image is displayed by the display module after the power-on signal is received, wherein the specific content is automatically selected according to a user access frequency based on the third predetermined self-refresh mode , wherein the selected content corresponds to content most frequently executed within a predetermined time; and wherein the self-refresh memory block corresponds to a memory block configured to be activated when the display device is deactivated. receiving (S1810) a power-off signal; storing (S1830) a system booting file and a predetermined snapshot image in a self-refresh memory block based on a predetermined self-refresh mode, wherein the predetermined snapshot image corresponds to at least one of an image of a content data, a default image and a specific content image; and wherein the predetermined self-refresh mode includes a first predetermined self-refresh mode , a second predetermined self-refresh mode ; and a third predetermined self-refresh mode ; receiving (S1840) a power-on signal; booting (S1850) a system by extracting the system booting file from the self-refresh memory block ; and controlling, by a controller , a display module in the display device to display (S1860) one of the predetermined snapshot images based on one of the predetermined self-refresh modes, wherein the content data is contiguously displayed by the display module when the power-off signal is received based on the first predetermined self-refresh mode , wherein the default image is displayed by the display module after the power-on signal is received based on the second predetermined self-refresh mode, wherein the specific content image is displayed by the display module after the power-on signal is received, wherein the specific content is automatically selected according to a user access frequency based on the third predetermined self-refresh mode , wherein the selected content corresponds to content most frequently executed within a predetermined time; and wherein the self-refresh memory block corresponds to a memory block configured to be activated when the display device is deactivated. <EOS>