The Camera app stores photos in some DCIM folder, and these can easily be accessed to attach to an email message, or to download to a pc over an USB cable.
In the Photos app, I can edit a photo, and save it as a separate photo file, and can see it among the unedited photo's and attach it to emails.
However, those edited photos are not visible over the USB connection, and cannot be downloaded to a pc.
It seems as if only the Camera app can store in the DCIM folders, but other apps can read files from that folder. Is it true that other apps cannot store in DCIM? Is the photo editor part of the Camera app? I did not yet try other photo editor apps.
Related problem is that the app Kopie ID from the dutch government cannot store the edited photo of an ID in DCIM so that you cannot upload it in a browser web app. (Purpose of this app is to be able to black out unneeded sensitive info, and to add a watermark)
I guess that android tries to play it more safe than good old unix / dos, where the file is the basic unit of info and the directory structure allows for very flexible file sharing between arbitrary apps.
Thanks for any hints on sharing files between phone and pc, and between apps.