I was playing with Cartoon Animator4 , it allow you to lauch an external image editor to create or import or modify image (PSD image).
As I use (and like) Affinity Designer, I tried to use it with CA4 but I noticed that when you finish to edit the image and try to go back to CA4, the image is not transferred to CA. In other words, the sync between the 2 application doesn't work.
The solution (in Affinity Designer) is this:
1. go to menu "Edit" - "Preferences" - "General"
2. find and select the option "Enable 'Save' over imported PSD files"
3. close settings window
Now it should work.
The reason is that when you start AD from CA, it opens a temporary .PSD file , but AD is not able to save over a .psd file by default, it asks you to save the file as .afdesign , and in a different folder, not the temporary one used by CA.
Changing the program settings allow AD to save the same temporary .PSD file used by CA, making the Sync feature working.