A method and system is described for creating a mask that isolates a region of interest in a digital image. The mask is created using a second underlay image that is initialized to 255 pixel values (white). A user identifies a region of interest in the digital image by drawing a closed curve around the region of interest. The same closed curve is created automatically on the underlay image with black pixel values for the curve. The pixels in the underlay image in the area between the closed curve and the border of the underlay image are assigned pixel values equal to minimum pixel value (black). The pixels in the interior of the underlay image have 255 pixel values (white), due to the initialization of the underlay image. The mask is applied to the original image by a summing operation. Image details peripheral to the region of interest are removed, while the region of interest pixels remain undisturbed.