Image editor error

I have a small problem with a photo editor app, I combined two apps when I save changes the app crashes, it's a simple problem that can be solved in 30 minutes I have a photo editor app, and I wanted to combine it with another photo editor app, I added some code to connect them, but my programming experience is weak. When I merge them, the image is sent from the first application to the other application well, and when I edit the image in the second application and save the changes to return the image to the first application, the application crashes. I don't know if the codes I added are wrong, but you can delete them and add new codes to link between the two applications.