On PC:
have them sorted in filemanager, select them all, drag them to the uploader page (you can alt-tab while dragging to show the uploader page). Let’s say there are 10 observations of 4 photos each. Typically each observation would have had it’s photos taken in succession, so in the uploader they should all be next to each other, assuming date order in filemanager. For the first observation, pick which is the first photo, and then drag the 2nd photo onto the first, then drag the third photo onto it, and so on in the order you want them to be. Then do the same for obs#2-10. Put IDs, descriptions and fields etc once each observation is grouped, or wait until all the grouping is done.