You could drag and drop them in the upload page, of course, although that would be pretty tedious. The upload page should import them in the order which their displayed on your computer. So after I’ve exported my photos, they looks like this on my mac:
If I drag those into the uploader (or use the dialog box to choose them) they appear in that order in the uploader.
@edhass it looks like you use Lightroom, so I’d recommend using the geotagging method shown here to get locations for your observations. I can’t tell you how much easier it’s made my iNatting.