During the late phases of evolution, low-to-intermediate mass stars like our Sun undergo periods of extensive mass loss, returning up to 80% of their initial mass to the interstellar medium. This mass loss profoundly affects the stellar evolutionary history, and the resulting circumstellar ejecta are a primary source of dust and heavy element enrichment in the Galaxy. However, many details concerning the physics of late-stage stellar mass loss remain poorly understood, including the wind launching mechanism(s), the mass loss geometry and timescales, and the mass loss histories of stars of various initial masses. These uncertainties have implications for stellar astrophysics, as well as fields ranging from star formation to extragalactic astronomy and cosmology. Observations at cm through sub-mm wavelengths that resolve the surfaces and extended atmospheres of evolved stars in space, time, and frequency are able to provide unique and powerful insights into these questions. I will describe results from recent resolved imaging observations of nearby evolved giants using the VLA and ALMA that exploit new advances in radio imaging methods. I will also discuss the exciting prospects for advances in stellar imaging that will come from new and upgraded radio wavelength facilities in the coming decade.