A method of controlling the display of an image by a head-mounted display, HMD, wherein the HMD comprises an input unit, a display unit, a sensor unit, and a controller, the method comprising: displaying a portion of an image on the display unit, wherein the portion corresponds to a user's field of view within the image; detecting a magnification request or a reduction request input through the input unit; if a magnification request is detected, displaying, on the display unit, the portion of the image magnified by the controller in accordance with the magnification request; identifying, by the controller, a value of the magnification rate of the magnified portion of the image; detecting, through the sensor unit, a movement of the HMD in at least one direction of up, down, left, and right; determining, by the controller, when the movement of the HMD is detected, a movement amount of the HMD along an X-axis and a Y-axis, wherein movement in an up or down direction corresponds to movement along the Y-axis and movement in a left or right direction corresponds to movement along the X-axis of the HMD; determining, by the controller, a display portion movement amount of the portion of the image along an X-axis and a Y-axis of the image based on the value of the magnification rate and the movement amount of the HMD along the X-axis and the Y-axis; and displaying, on the display unit, a portion of the image which has been moved according to the determined display portion movement amount along the X-axis and Y-axis of the image, such that the user's field of view within the image has been moved according to the display portion movement amount, wherein the determining the display portion movement amount comprises: if the value of the magnification rate is less than or equal to a pre-configured value, the display portion movement amount along the X-axis and Y-axis of the image is identical to the movement amount of the HMD along the X-axis and Y-axis, and if the value of the magnification rate is greater than the pre-configured value, the display portion movement amount along the X-axis and Y-axis of the image is smaller than the movement amount of the HMD along the X-axis and Y-axis. displaying a portion of an image on the display unit, wherein the portion corresponds to a user's field of view within the image; detecting a magnification request or a reduction request input through the input unit; if a magnification request is detected, displaying, on the display unit, the portion of the image magnified by the controller in accordance with the magnification request; identifying, by the controller, a value of the magnification rate of the magnified portion of the image; detecting, through the sensor unit, a movement of the HMD in at least one direction of up, down, left, and right; determining, by the controller, when the movement of the HMD is detected, a movement amount of the HMD along an X-axis and a Y-axis, wherein movement in an up or down direction corresponds to movement along the Y-axis and movement in a left or right direction corresponds to movement along the X-axis of the HMD; determining, by the controller, a display portion movement amount of the portion of the image along an X-axis and a Y-axis of the image based on the value of the magnification rate and the movement amount of the HMD along the X-axis and the Y-axis; and displaying, on the display unit, a portion of the image which has been moved according to the determined display portion movement amount along the X-axis and Y-axis of the image, such that the user's field of view within the image has been moved according to the display portion movement amount, wherein the determining the display portion movement amount comprises: if the value of the magnification rate is less than or equal to a pre-configured value, the display portion movement amount along the X-axis and Y-axis of the image is identical to the movement amount of the HMD along the X-axis and Y-axis, and if the value of the magnification rate is greater than the pre-configured value, the display portion movement amount along the X-axis and Y-axis of the image is smaller than the movement amount of the HMD along the X-axis and Y-axis. if the value of the magnification rate is less than or equal to a pre-configured value, the display portion movement amount along the X-axis and Y-axis of the image is identical to the movement amount of the HMD along the X-axis and Y-axis, and if the value of the magnification rate is greater than the pre-configured value, the display portion movement amount along the X-axis and Y-axis of the image is smaller than the movement amount of the HMD along the X-axis and Y-axis.