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Relativistic jets throughout the Universe transport energy from a galaxy's central supermassive black hole to extragalactic distances. Many jets, including the spectacular jet from the giant elliptical galaxy M87, are thought to be launched via the Blandford-Znajek (BZ) mechanism, where magnetic fields extract the black hole's spin energy. However, BZ energy extraction has never been confirmed observationally. In this talk, I will discuss how resolved images of supermassive black holes from the Event Horizon Telescope (EHT) are addressing long-standing questions about black hole accretion, magnetic fields, and jet launching. I will discuss how we obtain direct black hole images and how we interpret them with both analytic models and large-scale simulations. Connecting images to simulations indicates that in both M87 and the Galactic Center black hole Sgr A* the accreting plasma is arrested by strong coherent magnetic fields. I will show how the pattern of linear polarization in black hole images directly probes the direction of electromagnetic energy flux and encodes the black hole spin. I will also discuss how recent advances in simulating magnetically arrested accretion around black holes – including better coupling of gas-dominated and magnetically-dominated plasma and self-consistent electron-ion thermodynamics – are improving our ability to make sense of near-horizon images while raising new puzzles. I will show how future observations with the expanding EHT and the Black Hole Explorer (BHEX) space mission will increase the resolution and sensitivity of near-horizon images, expanding the sample of resolved black hole shadows and enabling precision measurements of black hole spin and jet launching in M87. Advances in horizon-scale theory and data over the next few years present an unprecedented opportunity to directly map out black hole magnetospheres and determine whether or not jets are powered by black hole spin energy extraction.