Comparison of Io in two cases with similar System III longitudes and Earth-Jupiter-Io phase angles. Images are orientated with north upwards and west to the right. The direction towards the centre of Jupiter in the image is indicated by a short cyan line. The short magenta line centred on Io indicates the apparent direction of movement of Io in the image. The dashed blue ellipse represents the plane perpendicular to the local magnetic field at Io according to an observer on Earth, and the blue line between the centre of Io and the edge of this ellipse is the projection of the movement vector of Io in this plane. Green lines represent detected jet-like structures. Panel a: 11 January 2015 (θ_{S 3} = 5°, ϕ_E = 68°). Panel b: 22 December 2022 (θ_{S 3} = 11°, ϕ_E = 67°).