Those are put there supposedly by date.. though I'm not sure... I think if you went into files and find the pics, and edit the info on the photo... but I'm not sure.
DROID RAZR MAXXIMIZED!!!! PREPARE TO BE VANQUISHED!!!
Like 94lt1 said, it seems to be by date - the oldest photos available are automatically displayed, regardless of folder or .nomedia file. I tried, but haven't found a way to change this, short of cut/pasting the photos from folder to folder to change their date created.