Instagram for iOS received an update today in support of iOS 7. The UI of the app hasn’t changed as far as button placement, but you will notice slight differences in how photos and videos are displayed. For one, every piece of posted content now extends to the corners of your screen. Before now, there was white space on either side. The bump in picture size also means the uploaded images have more resolution.
Outside of “everything is a little bigger,” nothing else of note has changed. Sure the profile icons are circular, but I doubt you care about that.
Source [Instagram Blog]