<Li> vector - based pen tools, </Li> <P> as well as more advanced facilities such as edge detection, masking, alpha compositing, and color and channel - based extraction . The border of a selected area in an image is often animated with the marching ants effect to help the user to distinguish the selection border from the image background . </P> <P> Another feature common to many graphics applications is that of Layers, which are analogous to sheets of transparent acetate (each containing separate elements that make up a combined picture), stacked on top of each other, each capable of being individually positioned, altered and blended with the layers below, without affecting any of the elements on the other layers . This is a fundamental workflow which has become the norm for the majority of programs on the market today, and enables maximum flexibility for the user while maintaining non-destructive editing principles and ease of use . </P> <P> Image editors can resize images in a process often called image scaling, making them larger, or smaller . High image resolution cameras can produce large images which are often reduced in size for Internet use . Image editor programs use a mathematical process called resampling to calculate new pixel values whose spacing is larger or smaller than the original pixel values . Images for Internet use are kept small, say 640 x 480 pixels which would equal 0.3 megapixels . </P>

Features of image editing tools as used in multimedia