What do layer styles like "Drop Shadow" do?

Layer styles like "Drop Shadow" are designed to enhance visual aesthetics by creating an illusion of depth in a design. When applied to a layer, the Drop Shadow effect simulates the appearance of a shadow cast by the layer's content. This effect gives the impression that the layer is raised above the background or other layers, adding dimension and making the elements stand out.

This three-dimensional effect is crucial in graphic design, as it helps guide the viewer's eye and can enhance the readability of text or the focus on key elements in an image. The shadow can be adjusted for opacity, distance, spread, and size, allowing for customization to achieve the desired visual outcome.

Looking at the other options, adding a color filter over the entire image does not pertain to the functionality of layer styles, which target specific layers rather than the overall image. The idea of live blending of multiple images relates to different techniques, such as using blend modes, rather than to layer styles like Drop Shadow. Lastly, resizing a layer directly without affecting quality pertains more to vector graphics than to raster images typically manipulated in Photoshop, as changing the size of a rasterized layer can impact quality.