  We present models of Galactic Center emission in the vicinity of Sagittarius
A* that use parametrizations of the electron temperature or energy density.
These models include those inspired by two-temperature general relativistic
magnetohydrodynamic (GRMHD) simulations as well as jet-motivated prescriptions
generalizing equipartition of particle and magnetic energies. From these
models, we calculate spectra and images and classify them according to their
distinct observational features. Some models produce morphological and spectral
features, e.g., image sizes, the sub-mm bump and low frequency spectral slope
compatible with observations. Models with spectra consistent with observations
produce the most compact images, with the most prominent, asymmetric photon
rings. Limb brightened outflows are also visible in many models. Of all the
models we consider, that which represents the current data the best is one in
which electrons are relativistically hot when magnetic pressure is larger than
the thermal pressure, but cold (i.e., negligibly contributing to the emission)
otherwise. This work is part of a series also applying the "observing"
simulations methodology to near-horizon regions of supermassive black holes in
M87 and 3C 279.
