Perspective (this is a view from up/downsides, where the clouds/atmosphere behaves differently), and, I presume, different colour processing (fitting the colour spectrum into what is visible to the human eye, which is not necessarily straightforward).

You can see that it’s a shot from one of the poles. Also, keep in mind that while the patterns in weather last a long time, they aren’t set in stone. The way Jupiter looks slowly changes over time, just like any other planet. Even the Big Red Spot hasn’t been there forever, and will eventually disappear.

Good question. I went looking for a source and am going to stop now but here are some links.

I suspect the source is one of the social media links here:

https://www.missionjuno.swri.edu/junocam/processing?id=17921

It doesn’t give much info for the specifics of how it was processed:

This processed view enhances cloud-top texture and reveals swirling filaments, compact vortices, and bright high-altitude clouds embedded in a chaotic flow.

It does list the source data for processing as this:

https://www.missionjuno.swri.edu/junocam/processing?id=JNCE_2023250_54C00143_V01

Here is a brief summary of the instrument from one of the groups involved with the Junocam:

https://www.msss.com/all_projects/junocam.php