We've confirmed that FxCamera's gallery is crushed on some devices. We are working on it and it will be fixed at the future version.
An alternative way is to use your pre-installed viewer app. find "Gallery", "Media Gallery" or "Album" at your home screen. the pictures taken by FxCamera will be stored in "FxCamera" folder.
Or, remove thumbnail folder on your SD card (remove /sdcard/dcim/.thumbnail ). It might be solve your problem because sometimes thumbnail folder is broken and cannot show pictures correctly. I believe it's a bug of Android (click here to watch the issue tracker)