A method for facilitating user customization of the image content of an image container from one or more displayed user-customizable image containers (302, 304), each image container characterized by an associated height-to-width ratio and each image container having associated therewith a base image (502, 702, 802, 900) and cropping information identifying at least position of the base image as content of the image container (302, 304), the method comprising: allowing a user to select an image container for customization of the content of the image container; allowing the user to request to perform custom cropping for the selected image container; in response to the user request, displaying the associated base image and a cropping indicator (504, 704, 804, 902) characterized by a box shape having four corners (506-512, 706-712, 904-910) and a height-to-width ratio which matches of the height-to-width ratio of the selected image container and positioned over the base image to indicate to the user the portion of the base image that is the current content in the image container (302, 304); allowing a user to modify the size of the cropping indicator box (504, 704, 804, 902) relative to the base image while maintaining the height-to-width ratio of the selected image container, updating the cropping information identifying the position of the base image indicated by the modified cropping indicator box in response to a modification of the size of the cropping indicator box (504, 704, 804, 902), the method characterized in that in response to the modification of the size of the cropping indicator box, each modified corner position of the cropping indicator is determined by: detecting selection of a corner (506-512, 706-712, 904-910) of the indicator box by a mouse pointer, calculating a slope line (912, 914) between the selected corner and its opposite corner of the indicator box, and repetitively monitoring a current position of the mouse pointer on the display, calculating a point of intersection on the slope line between the slope line and a perpendicular line between the current mouse pointer position and the slope line, positioning the selected corner at the calculated point of intersection, calculating the positions of the corners (904', 908') of the indicator box that are adjacent to the selected corner so as to maintain the height-to-width ratio of the indicator box to match the height-to-width ratio of the image container, and updating the display of the indicator box over the base image with the modified positions of the corners of the indicator box. detecting selection of a corner (506-512, 706-712, 904-910) of the indicator box by a mouse pointer, calculating a slope line (912, 914) between the selected corner and its opposite corner of the indicator box, and repetitively monitoring a current position of the mouse pointer on the display, calculating a point of intersection on the slope line between the slope line and a perpendicular line between the current mouse pointer position and the slope line, positioning the selected corner at the calculated point of intersection, calculating the positions of the corners (904', 908') of the indicator box that are adjacent to the selected corner so as to maintain the height-to-width ratio of the indicator box to match the height-to-width ratio of the image container, and updating the display of the indicator box over the base image with the modified positions of the corners of the indicator box.