I know it's not optimal, but why not just switch to a different gallery tool such as QuickPic? Its built-in editor is excellent, and the gallery management allows you a lot of flexibility, including picking up images from other sources/apps on your phone. Or install the Google Photos tool, which I use just for the editor. When I choose to edit an image (browse to & viewed in QuickPic), I have 3 apps that I regularly use to edit: QuickPic, Google Photos, and Paper Artist.
Anyways, the built-in photo editor should not crash, for sure, but it's really not worth trying to fix, as there are so many good options out there.