Hi there! The new version of Shy selfie 1.1 is comming. App has been submited to AppStore review. I think its about one or two weeks and will be available for you. BUT I can show you now, what will be possible in new version.
Finally preview can be square and you can adjust the radius of corner. Its possible to prepare preview to be as app icon, after that, just set your homescreen screenshot as app background and its done! Check the results below:) ( on the preview next to Messenger app, my lovely wife