Starshade Imaging Simulation Toolkit for Exoplanet Reconnaissance (SISTER) is a versatile tool designed to provide accurate models of the images of exoplanet systems when observed with a starshade positioned to block the light from the host star. SISTER allows one to control a set of observational parameters including: (1) the starshade design, position, orientation, and glint properties; (2) the telescope and optical system pupil, aberrations, bandpass, and throughput including a detector model; (3) the exoplanetary system, including stellar distance and spectral type, parallax and proper motion, planet size, reflection properties, orbital parameters, and exozodiacal dust; and (4) background objects. Additionally, there is a substantial library of built-in plotting software added, but the simulations may be stored on disk and plotted with any other software. We describe SISTER’s algorithms, its operational modules, and how it can be used to generate starshade optical simulations with a high degree of fidelity. We include some imaging examples.