Two experiments were conducted to test a prediction of the Kosslyn & Shwartz computer simulation model of mental image processing. According to this model, more complex images require more time to form because parts are placed sequentially, and larger images require more time to form than smaller ones because more parts are placed. If these accounts are correct, then the advantage of forming a small image (i.e., one that seems to subtend a smaller visual angle) should be greater for more (...) complex objects because the difference in number of parts imaged at the two sizes will be greater than with simpler objects. This prediction was confirmed only when subjects were not motivated to form highly elaborated images at small sizes. When subject tried to include all details, it actually took longest to form images of complex objects at small sizes. Both of these results support the central assumption of the Kosslyn‐Shwartz model, namely the existence of a fixed resolution analog spatial medium. (shrink)