I started to use photo express on my iPhone 6. When I edit a photo and save it it will not replace the original in the same sequence. How can I edit a photo and save it over the original in the same sequence in camera roll

[brianp33249]

‌i started to use photo express on my iPhone 6. When I edit a photo and save, it will not replace the original and not in the ame sequence. How can I edit, save to camera role in the same sequence?