The app has potential but is missing two or three must haves for iPhone photo related apps.
Missing is the ability to save a photo to your camera roll. You can download pictures to local app storage and then you have the choice to share it. When choosing that, the icons are missing for sharing options. Not a functional limitation but looks like there is an issue with the app. You can only share one photo at a time. This maybe limitation of some targets, but should not be all of them.
When previewing individual photos, you can tap a photo to enlarge it but then you don't have ability to swipe left or right to move through the list. This is a basic photo app navigation mechanism. Without this, the app is clunky and forces a lot of back and forth making it difficult to use. Additionally, in enlarged view mode you do not have typical functions. In other words, no pinch/un-pinch to zoom or tap and hold to save or share from there.
Basic functions of video preview and snapping pictures work well with one issue. It is not clear that pictures are local to the app or the device taking them. One odd thing is that you lose some features of the Camera like motion sensing when using the app with Wifi. This likely more a function missing in the camera versus the app, but some alignment of camera features and settings in app could help with this confusion.