Large multi-component mirrors are coming into widespread use as elements of optical systems. Initially used as light buckets, the introduction of precision mounting and control mechanisms allow for use in imaging systems. The optical parameters of "light buckets" are relatively straight forward: Light collection is a function of input cross section, and the diffraction effects are a function of individual component size and shape. The image parameters of multi-component mirror systems are a complex set of factors involving component size, shape, figure and lateral placement. Accurate longitudinal is required for coherent imaging. This paper discusses the image parameters of large, multi-component mirror systems both as excentricaly apertured segments of total mirror structure and as a summation of asymmetrical or tilted and decentered components. The two approaches yield comparable results.