For Mother's Day this year, my kids got my new up-to-date photos of them for my photo bulletin board! It was tricky though, because the pix I wanted were from our Instagram. They were coming out all stretchy and distorted when I tried to get them from Shutterfly :( But we figured out how to do it!
After selecting the photos we want to order, Shutterfly gives you a list of the pix - for you to select size and quantity; and you see a little thumbnail of how each pic will look. For your Instagram ones (which are square) click Preview under it. From the preview that pops up, choose cropping. At the bottom of the cropping window, it says Custom Tool - select that! Pick Square and you should be all set (make sure the whole pic is inside the square print area). They turned out great!! It will put them on the regular 4x6 print, but with a white border around it. Not blurry; not stretched :)