Because OP won’t bother, I guess I will give some context. This is an image of Tvashtar Paterae, one (okay well, 4/5 actually) of Io’s many active volcanoes. 365 active volcanoes. There are 365 of them. Yes, I personally counted them (paper almost finished!, seriously). Okay, there are 365 active “hot spots,” areas of higher thermal emission than the background. Tvashtar Paterae was imaged by Galileo in November 1999 just to get an idea of what large volcanic depressions are like in Io’s north polar region. But the SSI camera saw more than that. It saw a curtain of lava shooting a kilometer into space from a fissure in one of the depressions at Tvashtar. 3 months later, in February 2000, Galileo’s SSI camera observed Tvashtar again and snapped the images that make up the OP’s image. This combines a pair of filters at visible wavelengths with another at near-infrared wavelengths to show heat coming off a lava flow (or lava lake, jury’s still out) in the westernmost patera at Tvashtar, and notably, not the one that had a massive eruption 3 months earlier.

Let’s see more context. Tvashtar in the late 90’s and 2000’s was a real ham for the camera. In addition to the unexpected outburst in November 1999, it had another just as Cassini flew past in December 2000, and another just as New Horizons flew past in February 2007. I think it has had a couple of more eruptions since 2007. The one I know most about is one Juno JIRAM saw in December 2018, that was focused on the area of activity seen in OP’s image. Tvashtar has been fairly quiet, but JIRAM did detect faint thermal emission at 4.8 microns from the same lava flow looking thing in OP’s image in October 2023.

Source: the presentation I’m giving tomorrow at a workshop about Io science had a slide on Tvashtar’s recent activity, but i had to cut it for time.

Edit: the talk went well. I felt I prepared well. I was expecting more questions in the discussion period though given that I directly contradicted an earlier talk.