I was able to delete the Instant uploads folder from my galaxy s3 by the following manner:
1. On your phone, go to Settings - Accounts - Google
2. Click on your Gmail account shown.
3. Scroll all the way to the bottom and un-tick the checkbox against Sync Picasa Web Albums
4. On your computer, go to your Google+ account (same account used to setup your phone), navigate to photos and delete the album "Instant Uploads".
5. Follow steps 1 to 3 but on the last step, tick the checkbox against Sync Picasa Web Albums
6. Go to your gallery and the "Instant Uploads" folder should have been removed.
For those of you who are unable to see the check boxes when you get to step 3, your sync has been disabled. You can enable sync by the following steps:
1. Go to Settings - Data usage
2. Hit the menu key (the touch key on the left side of the Home button below the screen)
3. From the menu, click on "Auto sync data" and hit OK on the pop up info that follows.
Hopefully this will work for you as it did for me.