When you use the DJI Go4 app to save your stitched panorama to your gallery (Android - don’t know for iOS), it does do just that.
However … it’s not actually the one that the app already stitched together, but a far more compressed version.
Overall, it’s created 3 versions by the time it’s added one to the gallery.
Firstly, in … /DJI/dji.go.v4/CACHE_IMAGE/panoramaxxxresult/panorama.jpg
Then a version to … /DJI/dji.go.v4/DJI Albumpanorama_nnn.jpg
Then, when you ask it to save to your gallery, a version in … /Pictures/nnn.jpg
(where “xxx” = a 31 character alpha-numeric string, and “nnn” = a 31 character numeric string. I’ve no idea what these strings actually relate to. Not date/time or anything.)
But - whilst they are ALL 4096x2048, (1) and (2) are around 2MB, those in (3) are around 500KB.
Goodness knows why they make that modification … but goodness knows why DJI do many things that they do.
So - android users - you now know where to look for the best version.
File locations/names for other panos are the same, but this file size difference doesn’t seem to occur with the other panorama types that I have on my phone.
(Perhaps someone would check what happens on iOS?)