A computer-implemented method for obscuring two or more facial features of a subject in an image, the method comprising: detecting (202, 502) a head of the subject in the image; identifying (204, 504) a location of two or more facial features of the subject in the image; determining (206, 506) a region of the image to modify based on the location of the two or more facial features and based on a distance between the locations of the at least two facial features multiplied by a value of a predefined ratio, wherein the determined region comprises a part of the head on which the two or more facial features are located; and modifying (208, 508) the image within the determined region to obscure the two or more facial features, wherein identifying comprises: detecting a skin surface of the head of the subject in the image; and identifying a location of the one or more facial features on the detected skin surface of the head of the subject in the image, and wherein detecting the skin surface of the head of the subject in the image comprises: determining a convex hull for the head of the subject in the image; for one or more points on a surface of the convex hull, tracing a path inwardly or tracing the path outwardly from a point of the surface of the convex hull towards the centre of the head of the subject in the image; and detecting the skin surface of the head of the subject where a component of the image having a value greater than a background level for the image along the respective path is detected. detecting (202, 502) a head of the subject in the image; identifying (204, 504) a location of two or more facial features of the subject in the image; determining (206, 506) a region of the image to modify based on the location of the two or more facial features and based on a distance between the locations of the at least two facial features multiplied by a value of a predefined ratio, wherein the determined region comprises a part of the head on which the two or more facial features are located; and modifying (208, 508) the image within the determined region to obscure the two or more facial features, wherein identifying comprises: detecting a skin surface of the head of the subject in the image; and identifying a location of the one or more facial features on the detected skin surface of the head of the subject in the image, and wherein detecting the skin surface of the head of the subject in the image comprises: determining a convex hull for the head of the subject in the image; for one or more points on a surface of the convex hull, tracing a path inwardly or tracing the path outwardly from a point of the surface of the convex hull towards the centre of the head of the subject in the image; and detecting the skin surface of the head of the subject where a component of the image having a value greater than a background level for the image along the respective path is detected. determining a convex hull for the head of the subject in the image; for one or more points on a surface of the convex hull, tracing a path inwardly or tracing the path outwardly from a point of the surface of the convex hull towards the centre of the head of the subject in the image; and detecting the skin surface of the head of the subject where a component of the image having a value greater than a background level for the image along the respective path is detected.