Did it create an album in your gallery called Instant Uploads?
If so, it's because you either have Google+, Picasa or some other app synced and it's pulling old pics
To get rid of it try deleting the Google+ app, re-downloading it, make sure you don't enable instant upload and check that Picasa Albm isn't ticked in account & sync under your Gmail account.
To be extra sure, go into your settings and unsync everything.
Sync things one at a time, checking your gallery after each one to see which one creates the instant upload folder. Then keep that one unsynced.
Hope this works and helps.