H I gas distribution of perturbed galaxy NGC 4424 seen by ViCTORIA. For each resolution, we show the lowest reliable contour (3σ over a line width of 25 km s⁻¹). The contours are overlaid on an r-band image downloaded from the Legacy Survey database. The contour levels and resolutions are listed in the legend at the bottom, and the resolutions are shown in the top left corner. For comparison, we also show the lowest reliable H I contour from the VIVA survey (Chung et al. 2009), defined for consistency at a 3σ level over a line width of 25 km s⁻¹.