Ok since I'm clueless about Instagram...and I don't shoot cell phone shots. I've been finding out how to get photos that I've prepared for marketing purposes on to Instagram from the PC.
I found an easy way to get photos to your cell so you can instagram them is by using Picasa. Create a Blogger blog, use that as a photo dumping ground and Picasa (being another Google company) pulls them in.
I downloaded something called "Tool for Picasa, Google+ Photo" which makes it easy to organize any shots under the Google umbrella and then share to Instagram.
Maybe the Picasa/blogger part is redundant. I have to keep experimenting.