Zentrox88
Hello,
If you don't have another gallery app, may I suggest either:
GOS's own, new gallery app will be a fork/improvement of this:
https://github.com/IacobIonut01/Gallery
Or
https://github.com/FossifyOrg/Gallery
You should replace many of the default apps like contacts or get a calendar app, etc.
Anyway, if you screenshot and push edit, does it let you select the new app? If not, go to the app info of the photo editor it would/does open and do "clear defaults" inside "open by default"
If you really like the picture editor that you've been using, try reinstalling it.