Where is the Mac image editor?

There limited features in Photos Ap, but I recommend...

GraphicConverter has a powerful Browse Folder function, & many tools for manipulation, & you can keep your Pics wherever you want...

https://www.lemkesoft.de/en/products/graphicconverter/

http://www.lemkesoft.com/

There is none other than the limited editing you can do in Preview. There are however many third-party apps available. Some free, some not.