To demonstrate our analytical approach, we study Au wire electrodes immersed in an alkaline KOH electrolyte during cathodic CGDE, using high-speed camera imaging with and without background illumination. The images were evaluated using an open-source software package developed in-house based on Python. We discuss multiple aspects, such as the shape, size, distribution, and velocity of the discharges in the vapor layer, as well as the vapor layer itself, from a qualitative and quantitative evaluation of the images to the recorded currents. We also provide additional information on the ignition process of cathodic CGDE on wire electrodes.