The sampling of static visual content involves the sampling of both the color spectrum and space (usually in that order). The two are similar in that they both involve the discretization of continuous information. They are different in their dimensionality.

Should I add a formal definition of "color sampling" and "spatial sampling"?

The result of color sampling and spatial sampling is a matrix/table of picture elements (or pixels), each of which contains a single color in the palette. Such a matrix/table is often called a raster representation. One example is illustrated in the following Figure. In practice, sampled static visual content is usually created in one of two ways. In some cases, it is created using a scanner that samples from a source of some kind (e.g., a drawing or painting). In other cases, it is created on a computer by a person (who selects colors from a discrete set) using a pointing device of some kind (e.g., a mouse or a pen on a graphics tablet) that performs the spatial sampling. Two common examples of sampled static visual content are bitmapped images and bitmapped fonts.

Remember to add a figure that illustrates the different elements of a raster representation.