Final answer:
A common layer style in graphic editing programs like Adobe Photoshop is the drop shadow, which adds depth and visual interest to flat images.
Step-by-step explanation:
One common layer style that can be applied using graphic editing programs like Adobe Photoshop is drop shadow. This effect gives a two-dimensional object the illusion of depth by adding a shadow that appears to emanate from behind the object. Graphic designers often use drop shadows to enhance the visual hierarchy of elements in a layout, helping certain elements to stand out and creating a sense of three-dimensionality on what would otherwise be a flat image. Other common layer styles include outer glow, inner glow, bevel and emboss, and stroke, which are used to add various effects that enhance the visual appeal and clarity of graphic compositions.