Embodiments of the present disclosure provide a method, apparatus, and computer readable storage medium for processing an image. The method described herein includes determining a to-be-processed first region and a to-be-processed second region in an input image, the first region is at least partially filled with a first color, the second region is at least partially filled with a second color, and the first region and the second region are adjacent regions sharing a common boundary region. The method further includes shrinking the first region and the second region, to enable neither of the shrunken first region and the shrunken second region to include the boundary region. The method further comprises expanding the shrunken first region and the shrunken second region, to enable the boundary region to be filled with at least one color of the first color or the second color.