An image rendering method comprising: comparing a current image frame with a previous image frame to detect a dynamic change in an object in the image frames, with each image frame being defined by a scene graph and each object having an associated geometric bounding volume; if a dynamic change in an object is detected, rendering the object's geometric bounding volume to a stencil buffer for each dynamically changed object, the stencil buffer having a stencil register for each pixel; applying a stencil test to determine areas in the frames having non-zero stencil values; clearing a color buffer with respect to the areas in the previous image frame determined by the stencil test as having non-zero stencil values, the color buffer being for storing color information for each pixel and being comprised, along with a depth buffer for storing depth information for each pixel, in a frame buffer; rendering the image frame's geometry to the color buffer using a stencil test, so that only the areas with non-zero stencil values are redrawn; and removing the stencil values from a previous image frame from the stencil buffer, wherein the method uses N-buffer rendering and removing the stencil values from the previous image frame from the stencil buffer comprises removing stencil values for the frame rendered N frames before, wherein removing the stencil values comprises replacing non-zero values with zeroes, wherein a stencil value assigned to the current image frame is used in rendering the object's geometric bounding volume to the stencil buffer, wherein the method comprises assigning a stencil value of 1 for a first frame, a stencil value of 2 for a second frame, until a stencil value of N + 1 is used for the N + 1:th frame, and then repeating this for subsequent frames and in that further processing of fragments failing the stencil test is discarded. comparing a current image frame with a previous image frame to detect a dynamic change in an object in the image frames, with each image frame being defined by a scene graph and each object having an associated geometric bounding volume; if a dynamic change in an object is detected, rendering the object's geometric bounding volume to a stencil buffer for each dynamically changed object, the stencil buffer having a stencil register for each pixel; applying a stencil test to determine areas in the frames having non-zero stencil values; clearing a color buffer with respect to the areas in the previous image frame determined by the stencil test as having non-zero stencil values, the color buffer being for storing color information for each pixel and being comprised, along with a depth buffer for storing depth information for each pixel, in a frame buffer; rendering the image frame's geometry to the color buffer using a stencil test, so that only the areas with non-zero stencil values are redrawn; and removing the stencil values from a previous image frame from the stencil buffer, wherein the method uses N-buffer rendering and removing the stencil values from the previous image frame from the stencil buffer comprises removing stencil values for the frame rendered N frames before, wherein removing the stencil values comprises replacing non-zero values with zeroes, wherein a stencil value assigned to the current image frame is used in rendering the object's geometric bounding volume to the stencil buffer, wherein the method comprises assigning a stencil value of 1 for a first frame, a stencil value of 2 for a second frame, until a stencil value of N + 1 is used for the N + 1:th frame, and then repeating this for subsequent frames and in that further processing of fragments failing the stencil test is discarded.